On 04/04/2020 12:37, alan_m wrote:
On 04/04/2020 12:25, Andy Burns wrote:
D.M. Procida wrote:

What will loosen decades-old dried brass polish in fine crevices

I'd start with the same solvents that Brasso contains (white spirits
and ammonia)

and a tooth brush.


My late father was a dab hand at this sort of thing. Certainly a tooth
brush, I'd be inclined just to use water with perhaps a few drops of
washing up liquid. I think the purpose of ammonia and white spirit in
Brasso would be to attack fatty or greasy material. You might try
letting it soak.

I suspect the "abrasive" might be (or include) jeweller's rouge which is
an iron oxide, and perhaps chalk. So acids may have some effect, but you
really do not want to be attacking the metal.

If it is really hard to shift by hand you can get fibre brushes that fit
in a Dremel. Don't use wire brushes though!