Old memory cards with NiCad batteries... It's likely tha the card is already bewond repair from battery acid but to determin that you need to open the metal case and examin the card. Remove the battery if it shows leakage and clean of the card compleatly... then examin traces and if needed and possible repair dammaged ones.
The metal case can be replaced after "surgery".
In the end if it doesn't work is it worth putting the computer at risk of more damage when you can fetch a A500 memory card for about 5$ if you look around?
