I know, it's a bit of a weird one, but I've been plastering for years and am reasonably good at it (for an amateur!) but there's one thing I've never known... How on earth should I be cleaning the buckets afterwards?! Obviously I scoop out as much of the unused plaster as possible, put it in a bin bag and into the normal waste, then give the buckets a blast with the hose and a good scrub... But what should I do with the dirty water?! I've learnt the hard way that you can't just tip it in a drain as it can build up and cause a blockage... So what do the pros do?!