diff --git a/src/cc/Congruence_closure.ml b/src/cc/Congruence_closure.ml
index 2021f68b..a7656a16 100644
--- a/src/cc/Congruence_closure.ml
+++ b/src/cc/Congruence_closure.ml
@@ -17,15 +17,12 @@ let field_usr2 = Bits.mk_field()
 
 let () = Bits.freeze()
 
-type payload = Congruence_closure_intf.payload = ..
-
 module Make(A: ARG) = struct
   type term = A.Term.t
   type term_state = A.Term.state
   type lit = A.Lit.t
   type fun_ = A.Fun.t
   type proof = A.Proof.t
-  type value = A.Value.t
   type model = A.Model.t
 
   (** Actions available to the theory *)
@@ -47,7 +44,6 @@ module Make(A: ARG) = struct
     mutable n_size: int; (* size of the class *)
     mutable n_as_lit: lit option; (* TODO: put into payload? and only in root? *)
     mutable n_expl: explanation_forest_link; (* the rooted forest for explanations *)
-    mutable n_payload: payload list; (* list of theory payloads *)
     (* TODO: make a micro theory and move this inside *)
     mutable n_tags: (node * explanation) Util.Int_map.t;
     (* "distinct" tags (i.e. set of `(distinct t1…tn)` terms this belongs to *)
@@ -81,7 +77,6 @@ module Make(A: ARG) = struct
     let[@inline] equal (n1:t) n2 = T.equal n1.n_term n2.n_term
     let[@inline] hash n = T.hash n.n_term
     let[@inline] term n = n.n_term
-    let[@inline] payload n = n.n_payload
     let[@inline] pp out n = T.pp out n.n_term
     let[@inline] as_lit n = n.n_as_lit
 
@@ -94,7 +89,6 @@ module Make(A: ARG) = struct
         n_as_lit=None; (* TODO: provide a method to do it *)
         n_root=n;
         n_expl=FL_none;
-        n_payload=[];
         n_next=n;
         n_size=1;
         n_tags=Util.Int_map.empty;
@@ -120,35 +114,6 @@ module Make(A: ARG) = struct
       assert (is_root n);
       Bag.to_seq n.n_parents
 
-    type nonrec payload = payload = ..
-
-    let set_payload ?(can_erase=fun _->false) n e =
-      let rec aux = function
-        | [] -> [e]
-        | e' :: tail when can_erase e' -> e :: tail
-        | e' :: tail -> e' :: aux tail
-      in
-      n.n_payload <- aux n.n_payload
-
-    let payload_find ~f:p n =
-      let[@unroll 2] rec aux = function
-        | [] -> None
-        | e1 :: tail ->
-          match p e1 with
-          | Some _ as res -> res
-          | None -> aux tail
-      in
-      aux n.n_payload
-
-    let payload_pred ~f:p n =
-      begin match n.n_payload with
-        | [] -> false
-        | e :: _ when p e -> true
-        | _ :: e :: _ when p e -> true
-        | _ :: _ :: e :: _ when p e -> true
-        | l -> List.exists p l
-      end
-
     let[@inline] get_field f t = Bits.get f t.n_bits
     let[@inline] set_field f b t = t.n_bits <- Bits.set f b t.n_bits
   end
diff --git a/src/cc/Congruence_closure.mli b/src/cc/Congruence_closure.mli
index e9f38fbf..e2629ad5 100644
--- a/src/cc/Congruence_closure.mli
+++ b/src/cc/Congruence_closure.mli
@@ -3,8 +3,6 @@
 module type ARG = Congruence_closure_intf.ARG
 module type S = Congruence_closure_intf.S
 
-type payload = Congruence_closure_intf.payload = ..
-
 module Make(A: ARG)
   : S with type term = A.Term.t
        and type lit = A.Lit.t
diff --git a/src/cc/Congruence_closure_intf.ml b/src/cc/Congruence_closure_intf.ml
index 709d5f71..a4aad927 100644
--- a/src/cc/Congruence_closure_intf.ml
+++ b/src/cc/Congruence_closure_intf.ml
@@ -1,10 +1,7 @@
 
 module type ARG = CC_types.FULL
 
-(** Theory-extensible payloads in the equivalence classes *)
-type payload = ..
-
-module type S = sig
+module type S0 = sig
   type term_state
   type term
   type fun_
@@ -53,24 +50,18 @@ module type S = sig
     val iter_parents : t -> t Sequence.t
     (** Traverse the parents of the class.
         Invariant: [is_root n] (see {!find} below) *)
-
-    type nonrec payload = payload = ..
-
-    val payload_find: f:(payload -> 'a option) -> t -> 'a option
-
-    val payload_pred: f:(payload -> bool) -> t -> bool
-
-    val set_payload : ?can_erase:(payload -> bool) -> t -> payload -> unit
-    (** Add given payload
-        @param can_erase if provided, checks whether an existing value
-        is to be replaced instead of adding a new entry *)
   end
 
   module Expl : sig
     type t
     val pp : t Fmt.printer
 
-    (* TODO: expose constructors for micro theories to use *)
+    val mk_reduction : t
+    val mk_congruence : N.t -> N.t -> t
+    val mk_merge : N.t -> N.t -> t
+    val mk_merges : (N.t * N.t) list -> t
+    val mk_lit : lit -> t
+    val mk_lits : lit list -> t
   end
 
   type node = N.t
@@ -150,3 +141,10 @@ module type S = sig
   val pp_full : t Fmt.printer
   (**/**)
 end
+
+module type S = sig
+
+  include S0
+
+
+end
diff --git a/src/cc/Sidekick_cc.ml b/src/cc/Sidekick_cc.ml
index 595d635e..2f40100f 100644
--- a/src/cc/Sidekick_cc.ml
+++ b/src/cc/Sidekick_cc.ml
@@ -7,8 +7,6 @@ type ('f, 't, 'ts) view = ('f, 't, 'ts) CC_types.view =
   | Eq of 't * 't
   | Opaque of 't (* do not enter *)
 
-type payload = Congruence_closure.payload = ..
-
 module CC_types = CC_types
 
 (** Parameter for the congruence closure *)