Being in the auto repair industry 50+ years I have come across all kinds of stuff when removing seats, carpets, trim panels and upholstery. Now days I mostly find nasty food remains, dried up beverages, hair ties, small toys, pens and some coins. It is very rare that I would find any spare parts from the assembly line in a vehicle built in the last 25 years. Working on vehicles built in the 60's and 70's though yielded a treasure trove of spares parts. All kinds of clips, screws, rivets, nuts, bolts and other miscellaneous small parts were found in almost every vehicle you worked on.