Apparently you can remove rust stains from plastic work surfaces with lemon juice - didn't work when I tried it but maybe I needed a higher concentration of juice...
If you're cat's anything like mine you'll find he still can't work out where the litter tray is. I use a mixture of whitevinegar and water to blot up any 'accidents' and stop any smells.
Having hacked a finger off attempting to build some shelves I found that bloodstains can be removed from carpet by soaking in cold water, blotting with some kitchen roll and then finishing off with carpet shampoo - the finger got sewn back on...