I have no idea how long LSD would last on a surface, but I do know transdermal absorption is a thing. A friend of mine in college had it happen, but but he was

I have no idea how long LSD would last on a surface, but I do know transdermal absorption is a thing. A friend of mine in college had it happen, but but he was handling sheets with several hundred doses on them. It's also possible some transferred to his fingers and made its way to his mouth. If there were an accidental dosing, I suspect the original dosage would have been quite high. Anecdotally, I can say that taking a thin sheet smaller than the end of a pencil eraser I tripped for a solid 4-5 hours. LSD dosage and purity varies greatly, but where it used to be cheap and strong from what I understand it's quite difficult to find "good" LSD now.