diff --git a/src/proto_alpha/lib_parameters/default_parameters.ml b/src/proto_alpha/lib_parameters/default_parameters.ml
index 2ea7877721f755da6f157d3a1e12b93d3afbe1c1..366a3067671f3121cd0ff0453d5d518420e9c58e 100644
--- a/src/proto_alpha/lib_parameters/default_parameters.ml
+++ b/src/proto_alpha/lib_parameters/default_parameters.ml
@@ -180,7 +180,7 @@ let constants_mainnet : Constants.Parametric.t =
   in
   let sc_rollup = make_sc_rollup_parameter ~dal_activation_level block_time in
   {
-    consensus_rights_delay = 5;
+    consensus_rights_delay = 2;
     blocks_preservation_cycles = 1;
     delegate_parameters_activation_delay = 5;
     blocks_per_cycle = 24576l;
diff --git a/src/proto_alpha/lib_protocol/delegate_sampler.ml b/src/proto_alpha/lib_protocol/delegate_sampler.ml
index d0adde3d981b887506b77fcd57ffce260b279d36..7ecece83bf89017c9fcfd11693ba9e884b0506ab 100644
--- a/src/proto_alpha/lib_protocol/delegate_sampler.ml
+++ b/src/proto_alpha/lib_protocol/delegate_sampler.ml
@@ -63,6 +63,13 @@ module Delegate_sampler_state = struct
     let id = identifier_of_cycle cycle in
     let*? ctxt = Cache.update ctxt id None in
     Storage.Delegate_sampler_state.remove_existing ctxt cycle
+
+  let remove ctxt cycle =
+    let open Lwt_result_syntax in
+    let id = identifier_of_cycle cycle in
+    let*? ctxt = Cache.update ctxt id None in
+    let*! ctxt = Storage.Delegate_sampler_state.remove ctxt cycle in
+    return ctxt
 end
 
 module Random = struct
@@ -239,6 +246,19 @@ let clear_outdated_sampling_data ctxt ~new_cycle =
       let* ctxt = Delegate_sampler_state.remove_existing ctxt outdated_cycle in
       Seed_storage.remove_for_cycle ctxt outdated_cycle
 
+let cleanup_values_for_protocol_p ctxt ~preserved_cycles ~consensus_rights_delay
+    ~new_cycle =
+  let open Lwt_result_syntax in
+  assert (Compare.Int.(consensus_rights_delay <= preserved_cycles)) ;
+  if Compare.Int.(consensus_rights_delay = preserved_cycles) then return ctxt
+  else
+    let start_cycle = Cycle_repr.add new_cycle (consensus_rights_delay + 1) in
+    let end_cycle = Cycle_repr.add new_cycle preserved_cycles in
+    List.fold_left_es
+      Delegate_sampler_state.remove
+      ctxt
+      Cycle_repr.(start_cycle ---> end_cycle)
+
 module For_RPC = struct
   let delegate_current_baking_power ctxt delegate =
     let open Lwt_result_syntax in
diff --git a/src/proto_alpha/lib_protocol/delegate_sampler.mli b/src/proto_alpha/lib_protocol/delegate_sampler.mli
index 8e1f9cd6426d7f01337e55bf85d22c58e6846bd9..801d20b58fafe16f7cc4b432aa351e3ce3943fbd 100644
--- a/src/proto_alpha/lib_protocol/delegate_sampler.mli
+++ b/src/proto_alpha/lib_protocol/delegate_sampler.mli
@@ -70,6 +70,13 @@ val clear_outdated_sampling_data :
 val select_distribution_for_cycle :
   Raw_context.t -> Cycle_repr.t -> Raw_context.t tzresult Lwt.t
 
+val cleanup_values_for_protocol_p :
+  Raw_context.t ->
+  preserved_cycles:int ->
+  consensus_rights_delay:int ->
+  new_cycle:Cycle_repr.t ->
+  Raw_context.t tzresult Lwt.t
+
 module For_RPC : sig
   (** The baking power for a given delegate computed from its current
     stake. *)
diff --git a/src/proto_alpha/lib_protocol/init_storage.ml b/src/proto_alpha/lib_protocol/init_storage.ml
index 08a2672a4a94a9744683dff4e54419a233e94908..a45af41e6d0d146bfe319fe68b1f3c34e06c2773 100644
--- a/src/proto_alpha/lib_protocol/init_storage.ml
+++ b/src/proto_alpha/lib_protocol/init_storage.ml
@@ -179,10 +179,48 @@ let clean_frozen_deposits_for_p ctxt =
   in
   Raw_context.update_tree ctxt contracts_index contracts_tree
 
+let cleanup_values_for_protocol_p ctxt
+    (previous_proto_constants : Constants_parametric_previous_repr.t option)
+    level =
+  let open Lwt_result_syntax in
+  let preserved_cycles =
+    let previous_proto_constants =
+      match previous_proto_constants with
+      | None ->
+          (* Shouldn't happen *)
+          failwith
+            "Internal error: cannot read previous protocol constants in \
+             context."
+      | Some c -> c
+    in
+    previous_proto_constants.preserved_cycles
+  in
+  let consensus_rights_delay = Constants_storage.consensus_rights_delay ctxt in
+  let new_cycle =
+    let next_level = Raw_level_repr.succ level in
+    let cycle_eras = Raw_context.cycle_eras ctxt in
+    (Level_repr.level_from_raw ~cycle_eras next_level).cycle
+  in
+  let* ctxt =
+    Stake_storage.cleanup_values_for_protocol_p
+      ctxt
+      ~preserved_cycles
+      ~consensus_rights_delay
+      ~new_cycle
+  in
+  let* ctxt =
+    Delegate_sampler.cleanup_values_for_protocol_p
+      ctxt
+      ~preserved_cycles
+      ~consensus_rights_delay
+      ~new_cycle
+  in
+  return ctxt
+
 let prepare_first_block chain_id ctxt ~typecheck_smart_contract
     ~typecheck_smart_rollup ~level ~timestamp ~predecessor =
   let open Lwt_result_syntax in
-  let* previous_protocol, ctxt =
+  let* previous_protocol, previous_proto_constants, ctxt =
     Raw_context.prepare_first_block ~level ~timestamp chain_id ctxt
   in
   let parametric = Raw_context.constants ctxt in
@@ -280,6 +318,9 @@ let prepare_first_block chain_id ctxt ~typecheck_smart_contract
         let* ctxt = migrate_staking_balance_and_active_delegates_for_p ctxt in
         let* ctxt = clean_frozen_deposits_for_p ctxt in
         let*! ctxt = Raw_context.remove ctxt ["last_snapshot"] in
+        let* ctxt =
+          cleanup_values_for_protocol_p ctxt previous_proto_constants level
+        in
         return (ctxt, [])
   in
   let* ctxt =
diff --git a/src/proto_alpha/lib_protocol/raw_context.ml b/src/proto_alpha/lib_protocol/raw_context.ml
index d5350aad160b37b244b12ca83899701d5aecf3bc..f771611dd1363f2ab865edb5c41b1faf43b37548 100644
--- a/src/proto_alpha/lib_protocol/raw_context.ml
+++ b/src/proto_alpha/lib_protocol/raw_context.ml
@@ -1011,7 +1011,7 @@ let update_cycle_eras ctxt level ~prev_blocks_per_cycle ~blocks_per_cycle
 let prepare_first_block ~level ~timestamp _chain_id ctxt =
   let open Lwt_result_syntax in
   let* previous_proto, ctxt = check_and_update_protocol_version ctxt in
-  let* ctxt =
+  let* ctxt, previous_proto_constants =
     match previous_proto with
     | Genesis param ->
         let*? first_level = Raw_level_repr.of_int32 level in
@@ -1026,7 +1026,7 @@ let prepare_first_block ~level ~timestamp _chain_id ctxt =
         let*? cycle_eras = Level_repr.create_cycle_eras [cycle_era] in
         let* ctxt = set_cycle_eras ctxt cycle_eras in
         let*! result = add_constants ctxt param.constants in
-        return result
+        return (result, None)
     | Oxford_018 ->
         let*! c = get_previous_protocol_constants ctxt in
 
@@ -1190,10 +1190,14 @@ let prepare_first_block ~level ~timestamp _chain_id ctxt =
           }
         in
         let direct_ticket_spending_enable = false in
+        let consensus_rights_delay =
+          (* We change the consensus_rights_delay value only for mainnet *)
+          if Compare.Int.(c.preserved_cycles = 5) then 2 else c.preserved_cycles
+        in
         let constants =
           Constants_parametric_repr.
             {
-              consensus_rights_delay = c.preserved_cycles;
+              consensus_rights_delay;
               blocks_preservation_cycles = 1;
               delegate_parameters_activation_delay = c.preserved_cycles;
               blocks_per_cycle = c.blocks_per_cycle;
@@ -1265,7 +1269,7 @@ let prepare_first_block ~level ~timestamp _chain_id ctxt =
           else return (ctxt, constants)
         in
         let*! ctxt = add_constants ctxt constants in
-        return ctxt
+        return (ctxt, Some c)
   in
   let+ ctxt =
     prepare
@@ -1275,7 +1279,7 @@ let prepare_first_block ~level ~timestamp _chain_id ctxt =
       ~timestamp
       ~adaptive_issuance_enable:false
   in
-  (previous_proto, ctxt)
+  (previous_proto, previous_proto_constants, ctxt)
 
 let activate ctxt h =
   let open Lwt_syntax in
diff --git a/src/proto_alpha/lib_protocol/raw_context.mli b/src/proto_alpha/lib_protocol/raw_context.mli
index 327b8ed2c0a28d5c4d98e235f88134517c015bb1..76a39cc234385210af5d31ad82eea384a05591ac 100644
--- a/src/proto_alpha/lib_protocol/raw_context.mli
+++ b/src/proto_alpha/lib_protocol/raw_context.mli
@@ -100,7 +100,8 @@ val prepare_first_block :
   timestamp:Time.t ->
   Chain_id.t ->
   Context.t ->
-  (previous_protocol * t) tzresult Lwt.t
+  (previous_protocol * Constants_parametric_previous_repr.t option * t) tzresult
+  Lwt.t
 
 val activate : t -> Protocol_hash.t -> t Lwt.t
 
diff --git a/src/proto_alpha/lib_protocol/stake_storage.ml b/src/proto_alpha/lib_protocol/stake_storage.ml
index b2995c36b7b743815df960c52d71662faab4a2b8..712a1aedf77059619ad99e6cf988e7220f3bc530 100644
--- a/src/proto_alpha/lib_protocol/stake_storage.ml
+++ b/src/proto_alpha/lib_protocol/stake_storage.ml
@@ -71,6 +71,15 @@ module Selected_distribution_for_cycle = struct
     let id = identifier_of_cycle cycle in
     let*? ctxt = Cache.update ctxt id None in
     Storage.Stake.Selected_distribution_for_cycle.remove_existing ctxt cycle
+
+  let remove ctxt cycle =
+    let open Lwt_result_syntax in
+    let id = identifier_of_cycle cycle in
+    let*? ctxt = Cache.update ctxt id None in
+    let*! ctxt =
+      Storage.Stake.Selected_distribution_for_cycle.remove ctxt cycle
+    in
+    return ctxt
 end
 
 let get_full_staking_balance = Storage.Stake.Staking_balance.get
@@ -263,6 +272,27 @@ let add_contract_delegated_stake ctxt contract amount =
   | None -> return ctxt
   | Some delegate -> add_delegated_stake ctxt delegate amount
 
+(* let's assume that consensus_rights_delay <= preserved_cycles;
+   we need to keep [ new_cycles; new_cycles + consensus_rights_delay ]
+   and remove the rest, i.e.,
+   [ new_cycles + consensus_rights_delay + 1; new_cycles + preserved_cycles ] *)
+let cleanup_values_for_protocol_p ctxt ~preserved_cycles ~consensus_rights_delay
+    ~new_cycle =
+  let open Lwt_result_syntax in
+  assert (Compare.Int.(consensus_rights_delay <= preserved_cycles)) ;
+  if Compare.Int.(consensus_rights_delay = preserved_cycles) then return ctxt
+  else
+    let start_cycle = Cycle_repr.add new_cycle (consensus_rights_delay + 1) in
+    let end_cycle = Cycle_repr.add new_cycle preserved_cycles in
+    List.fold_left_es
+      (fun ctxt cycle_to_clear ->
+        let*! ctxt =
+          Storage.Stake.Total_active_stake.remove ctxt cycle_to_clear
+        in
+        Selected_distribution_for_cycle.remove ctxt cycle_to_clear)
+      ctxt
+      Cycle_repr.(start_cycle ---> end_cycle)
+
 module For_RPC = struct
   let get_staking_balance ctxt delegate =
     let open Lwt_result_syntax in
diff --git a/src/proto_alpha/lib_protocol/stake_storage.mli b/src/proto_alpha/lib_protocol/stake_storage.mli
index 5dbf028bbc7bbec3c91f3befd65e99874dc74dfd..721e24698c6efdd87d2a047c51a2ca14c09dbe3d 100644
--- a/src/proto_alpha/lib_protocol/stake_storage.mli
+++ b/src/proto_alpha/lib_protocol/stake_storage.mli
@@ -143,6 +143,13 @@ val add_contract_delegated_stake :
 val remove_contract_delegated_stake :
   Raw_context.t -> Contract_repr.t -> Tez_repr.t -> Raw_context.t tzresult Lwt.t
 
+val cleanup_values_for_protocol_p :
+  Raw_context.t ->
+  preserved_cycles:int ->
+  consensus_rights_delay:int ->
+  new_cycle:Cycle_repr.t ->
+  Raw_context.t tzresult Lwt.t
+
 module For_RPC : sig
   val get_staking_balance :
     Raw_context.t -> Signature.Public_key_hash.t -> Tez_repr.t tzresult Lwt.t