Scratching the card with a knife? Using tootpast or vaseline on it?
All those are extremely good ways to ruin/destroy it for good.
Unless your card is sertified as been waterproof, you should never ever dip it in ANY liquid. Also, any liquid that can't cause corosion or shorts is likely to melt the casing or leave some residus that can cause many errors.
If the contacts are dirty, the first thing to do is to insert and remove it several times from the adaptor or device that use it.
If the card's contacts are coroded and dirty and the previous step did not work, you can try gently using an eraser on the contacts.
Electro
October 2013
howtomendit.com for free repair help, information and advice.
