Things You'll Need
Instructions
Check for a country name somewhere on the stamp. It may appear in another language. If so, look up the name in its original language to find an appropriate translation.
Look for notable national symbols or language cues. These will help narrow the possibilities of which countries the stamp may have come from.
Look up possible clues using keywords, symbols and country lists in a stamp catalog. Search online catalogs exist in case your print versions don't point you in the right direction.
Use a watermark tray to reveal otherwise invisible text or symbols, and repeat above steps using the new marks as clues.