diff --git a/source/network/NetClient.cpp b/source/network/NetClient.cpp
index da9b713afa..049ca1d052 100644
--- a/source/network/NetClient.cpp
+++ b/source/network/NetClient.cpp
@@ -77,8 +77,6 @@ CNetClient::CNetClient(CGame* game, const CStrW& username, const CStr& hostJID)
 {
 	m_Game->SetTurnManager(NULL); // delete the old local turn manager so we don't accidentally use it
 
-	JS_AddExtraGCRootsTracer(GetScriptInterface().GetGeneralJSContext(), CNetClient::Trace, this);
-
 	// Set up transitions for session
 	AddTransition(NCS_UNCONNECTED, (uint)NMT_CONNECT_COMPLETE, NCS_CONNECT, &OnConnect, this);
 
@@ -146,13 +144,6 @@ CNetClient::~CNetClient()
 		m_ClientTurnManager->OnDestroyConnection();
 
 	DestroyConnection();
-	JS_RemoveExtraGCRootsTracer(GetScriptInterface().GetGeneralJSContext(), CNetClient::Trace, this);
-}
-
-void CNetClient::TraceMember(JSTracer *trc)
-{
-	for (JS::Heap<JS::Value>& guiMessage : m_GuiMessageQueue)
-		JS::TraceEdge(trc, &guiMessage, "m_GuiMessageQueue");
 }
 
 void CNetClient::SetGamePassword(const CStr& hashedPassword)
@@ -366,7 +357,7 @@ void CNetClient::CheckServerConnection()
 	}
 }
 
-void CNetClient::GuiPoll(JS::MutableHandleValue ret)
+void CNetClient::GuiPoll(const ScriptRequest& rq, JS::MutableHandleValue ret)
 {
 	if (m_GuiMessageQueue.empty())
 	{
@@ -374,7 +365,7 @@ void CNetClient::GuiPoll(JS::MutableHandleValue ret)
 		return;
 	}
 
-	ret.set(m_GuiMessageQueue.front());
+	Script::ReadStructuredClone(rq, m_GuiMessageQueue.front(), ret);
 	m_GuiMessageQueue.pop_front();
 }
 
@@ -386,7 +377,7 @@ std::string CNetClient::TestReadGuiMessages()
 	JS::RootedValue msg(rq.cx);
 	while (true)
 	{
-		GuiPoll(&msg);
+		GuiPoll(rq, &msg);
 		if (msg.isUndefined())
 			break;
 		r += Script::ToString(rq, &msg) + "\n";
diff --git a/source/network/NetClient.h b/source/network/NetClient.h
index 0ba2ff1e58..4c8179b5f5 100644
--- a/source/network/NetClient.h
+++ b/source/network/NetClient.h
@@ -27,6 +27,7 @@
 #include "ps/CStr.h"
 #include "scriptinterface/Object.h"
 #include "scriptinterface/ScriptRequest.h"
+#include "scriptinterface/StructuredClone.h"
 
 #include <ctime>
 #include <deque>
@@ -81,19 +82,6 @@ public:
 
 	virtual ~CNetClient();
 
-	/**
-	 * We assume that adding a tracing function that's only called
-	 * during GC is better for performance than using a
-	 * PersistentRooted<T> where each value needs to be added to
-	 * the root set.
-	 */
-	static void Trace(JSTracer *trc, void *data)
-	{
-		reinterpret_cast<CNetClient*>(data)->TraceMember(trc);
-	}
-
-	void TraceMember(JSTracer *trc);
-
 	void SetControllerSecret(const std::string& secret);
 
 	bool IsController() const { return m_IsController; }
@@ -168,7 +156,7 @@ public:
 	 *
 	 * @return next message, or the value 'undefined' if the queue is empty
 	 */
-	void GuiPoll(JS::MutableHandleValue);
+	void GuiPoll(const ScriptRequest& rq, JS::MutableHandleValue ret);
 
 	/**
 	 * Add a message to the queue, to be read by GuiPoll.
@@ -181,7 +169,7 @@ public:
 
 		JS::RootedValue message(rq.cx);
 		Script::CreateObject(rq, &message, args...);
-		m_GuiMessageQueue.push_back(JS::Heap<JS::Value>(message));
+		m_GuiMessageQueue.push_back(Script::WriteStructuredClone(rq, message));
 	}
 
 	/**
@@ -356,7 +344,7 @@ private:
 	CStr m_GUID;
 
 	/// Queue of messages for GuiPoll
-	std::deque<JS::Heap<JS::Value>> m_GuiMessageQueue;
+	std::deque<Script::StructuredClone> m_GuiMessageQueue;
 
 	/// Serialized game state received when joining an in-progress game
 	std::string m_JoinSyncBuffer;
diff --git a/source/network/scripting/JSInterface_Network.cpp b/source/network/scripting/JSInterface_Network.cpp
index c06f42e9d2..9d97509d48 100644
--- a/source/network/scripting/JSInterface_Network.cpp
+++ b/source/network/scripting/JSInterface_Network.cpp
@@ -196,16 +196,14 @@ CStr GetPlayerGUID()
 	return g_NetClient->GetGUID();
 }
 
-JS::Value PollNetworkClient(const ScriptInterface& guiInterface)
+JS::Value PollNetworkClient(const ScriptRequest& rq)
 {
 	if (!g_NetClient)
 		return JS::UndefinedValue();
 
-	// Convert from net client context to GUI script context
-	ScriptRequest rqNet(g_NetClient->GetScriptInterface());
-	JS::RootedValue pollNet(rqNet.cx);
-	g_NetClient->GuiPoll(&pollNet);
-	return Script::CloneValueFromOtherCompartment(guiInterface, g_NetClient->GetScriptInterface(), pollNet);
+	JS::RootedValue message{rq.cx};
+	g_NetClient->GuiPoll(rq, &message);
+	return message;
 }
 
 void SendGameSetupMessage(const ScriptInterface& scriptInterface, JS::HandleValue attribs1)