Distinguishing Water-Activated And Self-Adhesive Stamps

Removing used stamps from paper can be a bit challenging because we have water-activated and self-adhesive stamps these days. I have acquired all the tools to carefully remove used stamps from paper. However, yesterday when I was removing a stamp on an envelope mailed from the UK using "un-du", assuming that the stamp was self-adhesive – the stamp had a modern-look – I had a hard time removing the stamp and wondered why. Then, it dawned on me that the stamp might be water-activated. I immediately dried the stamp and soaked it on water. Voila! The stamp easily slid off the paper after a few minutes.

Is there an easy way to determine whether a stamp is water-activated or self-adhesive? I'd hate to commit the same mistake. (I don't have this problem when handling older used stamps.)

In case anyone is curious, here is the stamp that prompted this topic.

As a rule to sheet stamps or gummed stamps or water activated stamps is the perforations sheet stamp are usually perforated the old way with a round hole and have a very pointed corner perfs.

With self adhesive stamp from a sheetlet or coil have a perforation that is die cut or perforation line cut as apposed to a hole. The corner perfs are blunt or a round corner perf that is a coil in Aussie stamps.

Hope I have been helpful. KGV

Thank you for the information, KGV. I appreciate your response.

Here's an illustration of the same design printed both ways. The one on the left is a water activated sheet stamp, the one on the right is self adhesive. Note the square-ish perforations on the self adhesive one. Others may have wavy line die-cuts. Most European self adhesives in my experience (such as the one pictured) soak off in water just fine. There are some exceptions, however. Most recent US self adhesives will not come off easily in water.

Fantastic example, ArtfulHinger. Thank you.