I recently bought a 1942-P wartime nickel in BU. But when I put it in my dansco album i saw a gold toning on the obv. and reverse. The next day, it was 75% gold toning, and now it pretty much completly covered in this toning. What can you make of this?

That is awfully quick! I assume no other coins in the same folder and environment have exibited this?

The closest thing I have had happen like that was with a clad Kennedy half. It was ok when I got it but started getting ugly, blotchy and brown almost immediately after I got it. I figured it had been dipped or something and not rinsed properly.

Nope the other coins i bought are fine.
I bought it at local coin shop. but has never happened before

That is ridiciously quick... I never heard any coin that toned that quick before... :|

Stu is correct - the coin has been dipped. Or - it has come into contact with some substance that is causing the toning. It's not your album by the way.

I recently left an uncurculated Sac on a piece of wood furnature that has never been varnished or painted and it toned much much quicker then usual. I don't know why but probably for some similar reason that your "no nickel" nickel toned.

There's all kinds of gasses coming out of wood, that affect coins.

There is one exception: mahogany, that wood is inert.

Therefor, coin cabinets are usually / always made of mahogany

I DID NOT know that. What about velvet lined boxes?

I think the gasses will pass the velvet easily.