Do not use wd40 on the pullies! It will spray out all over the belt. I did it once when I was 16, and so much wd40 got on the belt, it slipped off the pullies and completely shattered my electric fan lol.
Just spray some simple green on the belt and pullies the best you can, and then wipe it all down with a rag. It should be good enoough til you get to replace it.