I'm guessing someone has already figured this (or something similar) out already, but I was searching the forum for ideas on what to use to soak the grates without being way too deep and only found suggestions for garage bags. I found a large plastic saucer for under a potted plant at my local plant store for $17 which works great. You probably won't find them this big at Home Depot or Lowes, but a specialty store should have them.