i use winzer wurth type 10 or type 20 always works a trear on the frames
We use Champion from Craftex, pH 13.5, and takes the grime off in seconds.
www.restormate.co.uk
http://www.restormate.co.uk/epages/Store.sf/?ObjectPath=/Shops/15094/Products/CRAFT49/SubProducts/15094-29746-1I put two capfuls into a standard unger bucket and fill it 3/4 full, ideally with hot water, but cold water is fine.