Cleaning Brass by Electrolysis

[Nick]

This appears hard work and electrolysis attacks the zinc element of the brass leading to surface discolouration (i.e. the copper begins to show through).

I use horolene concentrate from a supplier like this....

http://www.cousinsuk.com/catalog/7/1125/1350.aspx

I mix one part Horolene with seven parts water and use it again and again until it no longer works.
Immerse the item in warn solution for 10-15 minutes. Repeat until clean.

Horolene is just ammonium oxalate with a bit of green liquid soap added - you can make it easily from an oxalic acid solution - a teaspoon of oxalic acid crystals in a cup of warm water - plus a few ml of concentrated domestic ammonia solution and a couple of teaspoons of green liquid soap.

Soak for about 10 minutes - not more, rise thoroughly with distilled water, then methylated spirits, then dry with a hair dryer etc.

You can make a litre for well under a quid - Horolene is about 20 quid /litre

Oxalic acid is widely used for bleaching wood in cabinet making and restoration (removing stains from oak etc.) - you can get it in loads of places - I bought my last lot from a well known auction site... also used by bee-keepers as a safe treatment for varroa infestations...

Note that oxalic acid is toxic and you should avoid getting on your hands...