diff --git a/README.md b/README.md
index 4400bac..eecf6fa 100644
--- a/README.md
+++ b/README.md
@@ -39,6 +39,8 @@ ChatGPT is aimed to support conversational scenarios: user can talk to ChatGPT w
 * *MessageLimit*: specifies how many messages for each conversation must be saved. When this limit is reached, oldest messages are automatically removed.
 * *MessageExpiration*: specifies the time interval used to maintain messages in cache, regardless their count.
 
+We can also set ChatGPT parameters for chat completion at startup. Check the [official documentation](https://platform.openai.com/docs/api-reference/chat/create) for the list of available parameters and their meaning.
+
 The configuration can be automatically read from [IConfiguration](https://learn.microsoft.com/en-us/dotnet/api/microsoft.extensions.configuration.iconfiguration), using for example a _ChatGPT_ section in the _appsettings.json_ file:
 
     "ChatGPT": {
@@ -141,7 +143,7 @@ Response streaming works by returning an [IAsyncEnumerable](https://learn.micros
 
 **Changing the assistant's behavior**
 
-ChatGPT supports messages with the *system* role to influence how the assistant should behave. For example, we can tell to ChatGPT something like that:
+ChatGPT supports messages with the _system_ role to influence how the assistant should behave. For example, we can tell to ChatGPT something like that:
 
 - You are an helpful assistant
 - Answer like Shakespeare
@@ -161,7 +163,9 @@ The *system* message does not count for messages limit number.
 
 Conversation history is automatically deleted when expiration time (specified by *MessageExpiration* property) is reached. However, if necessary it is possible to immediately clear the history:
 
-    await chatGptClient.DeleteConversationAsync(conversationId);
+    await chatGptClient.DeleteConversationAsync(conversationId, preserveSetup: false);
+
+The _preserveSetup_ argument allows to decide whether mantain also the _system_ message that has been set with the **SetupAsync** method (default: _false_).
 
 **Contribute**
 
diff --git a/samples/ChatGptBlazor.Wasm/ChatGptBlazor.Wasm.sln b/samples/ChatGptBlazor.Wasm/ChatGptBlazor.Wasm.sln
deleted file mode 100644
index ac19c6e..0000000
--- a/samples/ChatGptBlazor.Wasm/ChatGptBlazor.Wasm.sln
+++ /dev/null
@@ -1,25 +0,0 @@
-
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-MinimumVisualStudioVersion = 10.0.40219.1
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "ChatGptBlazor.Wasm", "ChatGptBlazor.Wasm.csproj", "{E082D7E8-EB1C-49D1-9B62-32D998B05C4B}"
-EndProject
-Global
-	GlobalSection(SolutionConfigurationPlatforms) = preSolution
-		Debug|Any CPU = Debug|Any CPU
-		Release|Any CPU = Release|Any CPU
-	EndGlobalSection
-	GlobalSection(ProjectConfigurationPlatforms) = postSolution
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-		{E082D7E8-EB1C-49D1-9B62-32D998B05C4B}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{E082D7E8-EB1C-49D1-9B62-32D998B05C4B}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{E082D7E8-EB1C-49D1-9B62-32D998B05C4B}.Release|Any CPU.Build.0 = Release|Any CPU
-	EndGlobalSection
-	GlobalSection(SolutionProperties) = preSolution
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diff --git a/src/ChatGptNet/ChatGptClient.cs b/src/ChatGptNet/ChatGptClient.cs
index ea3e135..a1efa07 100644
--- a/src/ChatGptNet/ChatGptClient.cs
+++ b/src/ChatGptNet/ChatGptClient.cs
@@ -180,9 +180,20 @@ public Task<IEnumerable<ChatGptMessage>> GetConversationAsync(Guid conversationI
         return Task.FromResult(messages);
     }
 
-    public Task DeleteConversationAsync(Guid conversationId)
+    public Task DeleteConversationAsync(Guid conversationId, bool preserveSetup = false)
     {
-        cache.Remove(conversationId);
+        if (!preserveSetup)
+        {
+            // We don't want to preserve setup message, so just deletes all the cache history.
+            cache.Remove(conversationId);
+        }
+        else if (cache.TryGetValue<List<ChatGptMessage>>(conversationId, out var messages))
+        {
+            // Removes all the messages, except system ones.
+            messages!.RemoveAll(m => m.Role != ChatGptRoles.System);
+            cache.Set(conversationId, messages, options.MessageExpiration);
+        }
+
         return Task.CompletedTask;
     }
 
diff --git a/src/ChatGptNet/IChatGptClient.cs b/src/ChatGptNet/IChatGptClient.cs
index 4130e24..5d9b755 100644
--- a/src/ChatGptNet/IChatGptClient.cs
+++ b/src/ChatGptNet/IChatGptClient.cs
@@ -110,6 +110,7 @@ Task<Guid> SetupAsync(string message)
     /// Deletes a chat conversation, clearing all the history.
     /// </summary>
     /// <param name="conversationId">The unique identifier of the conversation.</param>
+    /// <param name="preserveSetup"><see langword="true"/> to maintain the system message that has been specified with the <see cref="SetupAsync(Guid, string)"/> method.</param>
     /// <returns>The <see cref="Task"/> corresponding to the asynchronous operation.</returns>
-    Task DeleteConversationAsync(Guid conversationId);
+    Task DeleteConversationAsync(Guid conversationId, bool preserveSetup = false);
 }