Tonight I decided to give my 3 year old bowl its first vinegar clean as per the instructions in the EDC as under :-Add 1000 g vinegar and 1/4 tspn dishwashing detergent to the TM bowl. Cook for 1 hour 50ospeed 1. Apart from the blade unit which is still very dark, it came out looking better than my second bowl which hasn't had anywhere near the same amount of use so that one is now also undergoing the same transformation.I am using the same batch of mixture for the second bowl. Guess I can save it and use it again further down the track? - I hate wasting a litre of vinegar.