As a welder, much of my work straddles the line between art and mass production. I’ve made many, many beautiful welds that will never been seen by another person for at least the next 20 years, if ever. Some of the best that come to mind are stainless steel welds on industrial equipment that get buried under paint or insulation. I spent 3 years welding parts for US battleships and Navy cruisers as well as the occasional weird airforce part. Most of those welds will never been seen by living people after leaving my old shop.
That would be the wrong approach. First big problem is that cops or anyone else can wear gloves. Second, you aren’t really trying to prove who owned the drugs. You would be interested in proving that the space in which the drugs were found previously did not contain the drugs before the cops “found” them. That’s why bodycams are super important. Most evidence tampering cases boil down to “spot was clearly empty before cop mysteriously produces drugs from the same spot”