diff --git a/willow/src/api/BUILD b/willow/src/api/BUILD
index ef005b0..1c2cff4 100644
--- a/willow/src/api/BUILD
+++ b/willow/src/api/BUILD
@@ -58,7 +58,6 @@ cc_library(
         "@abseil-cpp//absl/memory",
         "@abseil-cpp//absl/status",
         "@abseil-cpp//absl/status:statusor",
-        "@abseil-cpp//absl/strings",
         "@cxx.rs//:core",
         "//willow/proto/willow:aggregation_config_cc_proto",
         "//willow/proto/willow:messages_cc_proto",
diff --git a/willow/src/api/server_accumulator.cc b/willow/src/api/server_accumulator.cc
index 8bc148a..d837e40 100644
--- a/willow/src/api/server_accumulator.cc
+++ b/willow/src/api/server_accumulator.cc
@@ -61,8 +61,8 @@ ServerAccumulator::CreateFromSerializedState(std::string serialized_state) {
 
 absl::Status ServerAccumulator::ProcessClientMessages(
     ClientMessageRange client_messages) {
-  auto serialized_client_messages = client_messages.SerializeAsString();
-  client_messages.Clear();
+  auto serialized_client_messages =
+      std::move(client_messages).SerializeAsString();
   return ProcessClientMessages(std::move(serialized_client_messages));
 }
 
@@ -167,4 +167,4 @@ absl::StatusOr<EncodedData> FinalResultDecryptor::Decrypt(
 }
 
 }  // namespace willow
-}  // namespace secure_aggregation
\ No newline at end of file
+}  // namespace secure_aggregation