A cast iron skillet can never be "ruined"..and letting it lay with
grease certainly won't hurt it...only water can damage it but even that
is fixable....

Put it in the oven with the hottest setting you stove has....leave it
for about 45 mins to an hour..turn off oven and let the pan cool down
with the oven......this retempers the pan..

remove cooled pan from oven and gently scrape off any remaining black
flakes...then coat inside and out with canola oil.....hang it on the
wall or a hook until you need to use it again...regrease it b/4 using it
with your choice of bacon fat, olive oil, butter, etc. every time you
use it.

NEVER, NEVER, NEVER wipe, rinse or clean it with water....after it
cools down from cooking, just wipe it out with a few paper towels til
the towel looks clean...

If you find one at a garage sale that is rusty, just use spain steel
wool and oil and scrub til all signs of rust are gone then generously
use the canola oil inside and out.....now you have another one to add to
your collection...don't pass them up just kuz they look bad...

I have a wall full of every size shape and use...from griddles, to corn
bread, to 4" to 12" fry pans, kettles, huge roasters and a sauce pot
which I use to bake bread in.....only one was purchased new !!!!! It
becomes an addictive hobby.....

http://community.webtv.net/R-J-Q/FIRSTANNUALALLYEAR

http://www.wtv-zone.com/cal555/index.html