On 04/08/2018 19:35, newshound wrote:
I don't think even the old Methylene Chloride "Nitromors" will touch the
worst of it. Boiling, strong sodium hydroxide solution probably gives
you the best chance. Not recommended unless you are used to handling
aggressive chemicals.

The lacquers from oxidised oils and greases are *very* chemically
resistant. Otherwise you are down to mechanical methods (wire brush,
sanding disk).

Sodium hydroxide, (dangerous, 1 drop in the eye and you are blinded)
I think this is what the `oven cleaner companies` use but in gel form to
avoid splashes.
it would help if the parts concerned could be diassembled and taken
outside and soaked in a tray for an hour.
Available on ebay:
https://www.ebay.co.uk/itm/Sodium-Hy...wAAOSwc2FaFepm