A501 Memory Expansion Card - Leak Work

This A501 memory expansion had a battery leak, so i had to do something. After some web search, i try to solve the problem.

See also:
Commodore Amiga 500: Amiga 500
A501 memory card expansion for the Amiga 500: A501 expansion card
New coin cell replacement: Soldering c. cell
A501 bug...real bug!!: A501 real bug

As you can see, i remove the battery and i have a dark area of leak.
I used the following ingredients: Lemon juice, (vinegar will also work), a toothbrush, some swabs and some clear nail varnish.

First clean the CPB gently, i used a toothbrush

Then a swab with the lemon juice, and scrub gently again

Let the lemon juice dry, wait some time.
Scrub now with the toothbrush with soap warm water

Wait some more time, let it dry well, wait some hours just in case
Apply clear nail varnish in all the area were you can see the leak and
let it dry again some hours