Ooo I never thought about sterilising tablets! One of my litter trays has some really stubborn stains on!
Strangely, anti dandruff shampoo gets the crusty stains off quite well :lol: :lol: :lol: . Don't ask how I discovered this useless little fact. It included a litter tray, a bathroom and me running out of vinegar :lol: :lol: .