Is There a Doctor in the House? - S3-E18
Continuity mistake: Hogan pulls a container with a red cross out of the drop box and opens it. It is labeled "penicillin" inside and contains among others several vials of clear liquid. Back in the camp, Hogan gives a box with a red cross on top to Kinchloe, saying "here's the penicillin." It is a completely different box.
Is There a Doctor in the House? - S3-E18
Revealing mistake: As Carter blows into the bottom of the oven, the suds that hit Newkirk in the face come out in a thin stream on top, not out of the whole stovepipe.
Is There a Doctor in the House? - S3-E18
Other mistake: As Carter gets ready to clean out the stove, Newkirk closes his eyes and winces just before the bellows Carter has blows.
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.