As the description of Wasteland Treasures Vol 3 states...
"Adds a chance to harvest acid from cars, medical equipment, and acid barrels."
"Medical equipment" is pretty vague though I will admit. Medical Cabinets, med piles, and chem piles are all working for me in A22. The probabilities may be a bit too low on the piles. Also, in reference to what RipClaw was saying, players shouldn't have to fiddle around that much to get the loot AND the harvest.
I'll make a note to see about reworking this for A22.
Thanks for the insight!