Errors - What To Look For??

I am primarily a collector of coins and currency but recently picked up a large stamp collection. Included in that collection is a hoard of literally thousands of stamps from the 1920;s-1960's. I realize most have little value but wondered if there are varieties or errors that I should look for? What resource is there to read up on errors and varieties? Thanks for any help.

Scott Catalogs work well for your basic information. For varieties specialist catalogs are usually needed but it all depends on the Country that issued the Stamp.

you could post some scans of your stamps and maybe we could help some?

If you find any of these... no NOT use them on your outgoing mail!

Is that yours, chasa?

I have an E perf gauge so I will scan a black stock page at 600dpi and I can check perfs as well as blow things up 200% to flyspec for minor details all at once. Of course you can go 1 at a time with 10-20 power loop but scans seem to easiest for doing a bunch at a time. Now as to what to look for - depending on what you have scotts is a good general start and then there is specialized editions for alot if not most of everything.