Cloud Storage is full? I can't save any replay both online or to local

[Marlon Brando]

I tried to upload a screenshot today , but Steam reminds me I have only 900kb left in my cloud storage and every time the game prompts me a message saying that my cloud storage is nearly full I need to delete replays. However, there is nothing in my local replay folder, and there is nothing I can do to clear the cloud storage. Because of that, the synchronization takes very long whenever I launch or quit the game. Is there any way I can clear the Steam cloud storage?