I was scratching around as per normal and found this rather ingenious coin tumbler... I like it, the design is sound and you won't break the bank building something like this... I'm battling trying to clean my coins, so far I've tried Acetone (slight success) and the vinegar/lemon mix, also with slight success.
Firstly here's the link to the entire article... It gives you all the details as to the 'how' and 'what', really informative.
http://www.tribemagazine.com/board/tribe-main-forum/165315-metal-detecting-treasure-hunting-south-africa-4.htmlRock tumblers are the best way to clean crusty modern coins. If you've ever seen tumble polished semiprecious stones before, they are made by putting rough rock in a tumbling barrel that rotates very slowly with some water and some grit and a little dish soap. After a while, the rough rock becomes smooth. Finer and finer grits are used, and eventually a polish stage with a chemical like cerum oxide which is ultra fine and gives the stones their shine.