Yes, I am very sorry that INSIDE was not the perfect description.
Next time I will write:
" ... to clean the contacts (and the 510 pin if it isn't a hybrid type) along with the threads and the switch internals ... "
thats more exact.

Today I used the same battery which I used in the " 7 days vinegar Nemi" in a SMPL,
and found a big delay in fireing.
The reason was lots of black hard plastic on battery minus.
No problem to remove the black plastic.
It seems the vinegar was aggressive to the Nemi plastic ring.

OK, 7 days for a Nemi in vinegar was too much, my fault.
But it shows how some parts react to vinegar.

And a special add for CC: the battery was not in the vinegar.

So far, we all got ideas, how to clean mech mods INSIDE.