Help with preparing these (hides)?

[Lolo76]

My roommate gave me two of his broken flowerpot saucers, since I mentioned they'd make good hides... both have perfect-sized openings broken off, but they are quite jagged & rough. How can I smooth the edges without any fancy tools? The fanciest tool I have is an electric drill, and I'm not about to buy anything just for this purpose.

Also, what's the best way to sanitize/clean them without bleach? We don't use bleach in our household (for a variety of reasons), mostly just natural cleaning products and soap. And finally, what size BPs would you suggest for these hides? I was thinking of giving the smaller one to Vinnie, my ~130g spider, and the bigger one for Rosalind the ~440g het. Whaddya think? Here are some pictures of them:





(The small cracks are superficial)