Counterfeit forever stamps are becoming abundant - updated

The embedded image is a scan of some of the 29c stamps I bought from a friend at our local stamp club this weekend.  I use a pair of the stamps (from the 1990s) to mail a standard first class letter.  I buy the stamps from my friend at 70% face, so basically I spend 40c to mail a letter.   I wrote about the mechanisms and economics of discount postage back in 2014.

Recently, as a result of advances in printing technology, the situation has taken a more sinister turn, with counterfeit forever stamps flooding the marketplace.  This image from Linn's Stamp News in the fall of 2021 shows a counterfeit forever stamp (on the left) next to a valid one:

The only difference visible to the human eye is a subtle difference in the sharpness of the printed letters.

In the past couple of decades, the most frequently encountered counterfeit stamp was the Flag stamp. Sellers, typically through online outlets, would sell bulk quantities of these stamps at a significant discount from face value... But in July [2021], the first counterfeit of a recent commemorative stamp surfaced. Some security features were even faked, but not the one item that triggers cancellation machines at processing centers... Based on inquiries I have received, the unsuspecting buyers are often offices looking for a deal on postage. Many counterfeit stamps I have found are on mail sent by coin dealers, many who use discount postage when sending their mail.

And another article, just this past month, notes that counterfeiters are now able to duplicate foil texture and other special features.

As of the publishing of this article, Linn’s has counted approximately 40 new counterfeit issues (180 stamp designs)... When compared to the authentic stamps, the counterfeits appear shinier. This is likely because of the lack of a taggant coating that sometimes mutes a stamp design...The other new twist is the use of a special glossy coating that provides texture to the counterfeit stamps. Examples of these have been reported for two issues: the eight 2017 Sports Balls forever stamps (Scott 5203-5210) and the 10 2021 Star Wars Droids forever stamps (5573-5582).  The gloss on both counterfeits seems thicker than that on the authentic stamps. Also, the offset printing of the counterfeits has a grainier appearance.

Most of these counterfeits are being offered in bulk sales to owners of small businesses, or involve high-denomination stamps.  Be wary of someone offering to sell recent stamps at significant discounts to the face value. 

Reposted from March 2022 to add two images.  The first shows examples of counterfeit Forever stamps alongside valid ones -

The image is a screencap from an hour-long American Philatelic Society video presentation on the ongoing epidemic of counterfeit stamps.  Please see the video for details about the detection of these items.

The second screencap is a take-home message advising Americans to beware of offers of deeply-discounted stamps on social media.  While it is unlikely that any naive person would be prosecuted for mail fraud after inadvertently using counterfeit stamps for personal mail, it is important to understand that the money used to purchase those counterfeits is going into the pockets of bad people in China and perhaps Russia.