I bought my old detective special years ago off of Gunbroker. It came to me in an old orange gun sleeve (the zip up kind) that had literally disintegrated on the inside. Little orange specks flew out all over when I opened it. I thought "What a jerk, sending out a gun in a beat up old case like this". When I got home I noticed some grittiness when pulling back the hammer, upon taking off the side plate I realized that someone had liberally applied grease to the inside of the gun and STORED it inside that old case. The grease had done a good job of gathering those specs and turning into a really nice sludge. I had to detail strip that old revolver and scrub off every part. I wish I had thought of taking pictures of it, I don't think anyone would believe me if I tried to describe the extent of the sludge.
Long story short, it should be legal to drive to the homes of people who don't clean guns before selling them and slap them.