[Healeys] Brake/Clutch Reservoir inside washer?

[Thomas Morrione]

Folks,

I9m rebuilding my BJ8 clutch/brake reservoir and see there9s an aluminum
washer on the outside of the can for the clutch and brake line nipples. But
on disassembly I found a black substance inside the can between the clutch
(small) cylinder reservoir bottom and the can inside bottom. It looks like a
very thin washer of some sort  perhaps butyl or neoprene.  I9ve looked in
the archives and see no mention of it and Moss doesn9t list the part.
Helpful listers I9ve asked have suggested making one  which I can do  but
my question is - is it supposed to be there  or is this likely just residue
from some sealant? (if it is what9s best to use?) There9s no washer inside
the can for the brake line.

TIA,
Tom
BJ8 65 in process