Dried crestie diet stuck in cage?

I used to have a crested gecko, but it sadly escaped and I never found him... But I was feeding him crested gecko diet, and when it dried it was IMPOSSIBLE to get out of the bowl! And it's on the bottom and sides of the tank, too. I'm about to get fire belly toads for the tank, but I can't get the stuff off! I tried scraping it, it doesn't work. Is there anything I can put on it? Should I just bleach the tank??