diff --git a/dune b/dune
index 815c0f49..1c6b45f6 100644
--- a/dune
+++ b/dune
@@ -1,3 +1,3 @@
 (env
  (_
-  (flags :standard -warn-error -a+8 -strict-sequence)))
+  (flags :standard -warn-error -a+8 -w +a-4-30-40-41-42-44-70 -strict-sequence)))
diff --git a/src/client-cohttp-lwt/common_.ml b/src/client-cohttp-lwt/common_.ml
index a082ff1f..091896aa 100644
--- a/src/client-cohttp-lwt/common_.ml
+++ b/src/client-cohttp-lwt/common_.ml
@@ -1,4 +1,3 @@
-open Lwt.Syntax
 module Atomic = Opentelemetry_atomic.Atomic
 
 let[@inline] ( let@ ) f x = f x
diff --git a/src/client-cohttp-lwt/opentelemetry_client_cohttp_lwt.ml b/src/client-cohttp-lwt/opentelemetry_client_cohttp_lwt.ml
index 11e93aed..2048db44 100644
--- a/src/client-cohttp-lwt/opentelemetry_client_cohttp_lwt.ml
+++ b/src/client-cohttp-lwt/opentelemetry_client_cohttp_lwt.ml
@@ -164,16 +164,8 @@ end
 module Batch : sig
   type 'a t
 
-  val push : 'a t -> 'a -> bool
-  (** [push batch x] pushes [x] into the batch, and heuristically
-      returns [true] if the batch is ready to be emitted (to know if we should
-      wake up the sending thread, if any) *)
-
   val push' : 'a t -> 'a -> unit
 
-  val is_ready : now:Mtime.t -> _ t -> bool
-  (** is the batch ready to be sent? This is heuristic. *)
-
   val pop_if_ready : ?force:bool -> now:Mtime.t -> 'a t -> 'a list option
   (** Is the batch ready to be emitted? If batching is disabled,
       this is true as soon as {!is_empty} is false. If a timeout is provided
@@ -205,8 +197,6 @@ end = struct
       high_watermark;
     }
 
-  let is_empty_ self = self.size = 0
-
   let timeout_expired_ ~now self : bool =
     match self.timeout with
     | Some t ->
@@ -219,8 +209,6 @@ end = struct
     | None -> self.size > 0
     | Some b -> self.size >= b
 
-  let is_ready ~now self : bool = is_full_ self || timeout_expired_ ~now self
-
   let pop_if_ready ?(force = false) ~now (self : _ t) : _ list option =
     if self.size > 0 && (force || is_full_ self || timeout_expired_ ~now self)
     then (
diff --git a/src/integrations/cohttp/opentelemetry_cohttp_lwt.ml b/src/integrations/cohttp/opentelemetry_cohttp_lwt.ml
index 1b0cf4ab..9adb3902 100644
--- a/src/integrations/cohttp/opentelemetry_cohttp_lwt.ml
+++ b/src/integrations/cohttp/opentelemetry_cohttp_lwt.ml
@@ -143,7 +143,6 @@ end = struct
       ?parent:(Option.map (fun scope -> scope.Otel.Trace.span_id) scope)
       ?links name
       (fun scope ->
-        let open Lwt.Syntax in
         let req = set_trace_context scope req in
         f req)
 end
@@ -152,7 +151,7 @@ let client ?(scope : Otel.Scope.t option) (module C : Cohttp_lwt.S.Client) =
   let module Traced = struct
     open Lwt.Syntax
 
-    let attrs_for ~uri ~meth () =
+    let attrs_for ~uri ~meth:_ () =
       [
         "http.method", `String (Code.string_of_method `GET);
         "http.url", `String (Uri.to_string uri);
diff --git a/src/lwt/opentelemetry_lwt.ml b/src/lwt/opentelemetry_lwt.ml
index 8e8524cf..f398b5fd 100644
--- a/src/lwt/opentelemetry_lwt.ml
+++ b/src/lwt/opentelemetry_lwt.ml
@@ -58,7 +58,6 @@ module Trace = struct
 end
 
 module Metrics = struct
-  open Proto.Metrics
   include Metrics
 end
 
diff --git a/src/opentelemetry.ml b/src/opentelemetry.ml
index 8fa159c5..38dc60e4 100644
--- a/src/opentelemetry.ml
+++ b/src/opentelemetry.ml
@@ -252,8 +252,6 @@ module Trace_id : sig
 
   val of_hex : string -> t
 end = struct
-  open Proto.Trace
-
   type t = bytes
 
   let to_bytes self = self
@@ -294,8 +292,6 @@ module Span_id : sig
 
   val of_hex : string -> t
 end = struct
-  open Proto.Trace
-
   type t = bytes
 
   let to_bytes self = self
diff --git a/src/thread_local.ml b/src/thread_local.ml
index f53fde6e..4c4eadfb 100644
--- a/src/thread_local.ml
+++ b/src/thread_local.ml
@@ -28,8 +28,6 @@ let[@inline] get_exn (self : _ t) =
 
 let[@inline] get self = try Some (get_exn self) with Not_found -> None
 
-let[@inline] get_or ~default self = try get_exn self with Not_found -> default
-
 (* remove reference for the key *)
 let remove_ref_ self key : unit =
   while
diff --git a/src/trace/opentelemetry_trace.ml b/src/trace/opentelemetry_trace.ml
index 16f4ccc4..5078fdc8 100644
--- a/src/trace/opentelemetry_trace.ml
+++ b/src/trace/opentelemetry_trace.ml
@@ -3,8 +3,6 @@ module TLS = Otel.Thread_local
 
 type span = Trace.span
 
-let ( let@ ) = ( @@ )
-
 (** Table indexed by Trace spans *)
 module Span_tbl = Hashtbl.Make (struct
   include Int64
@@ -119,7 +117,7 @@ let collector () : Trace.collector =
 
         ()
 
-    let message ?span ~data msg : unit =
+    let message ?span ~data:_ msg : unit =
       (* gather information from context *)
       let old_scope = Otel.Scope.get_surrounding () in
       let trace_id = Option.map (fun sc -> sc.Otel.Scope.trace_id) old_scope in