Hello, I'm new to this forum. I wish I had joined earlier to avoid problems with my plaster. I have stains, scaling and a nasty crack on a corner. I'm going to replaster either later this summer or at the beginning of next year. I've gotten 12 years out of the original plaster and was fine until last year when I used too much and the wrong algaecide. I thought I might try to sand a few bad areas to buy some time and enjoy the upcoming holidays. Any tips on sanding would be much appreciated. Grit, hand vs power etc.