In the motor trade you do see everything left in vehicles, saddly after accidents very rarely the occasional body part, teeth etc but usually the fire brigade ambulance folk tidy up after todays accidents.
Having a police compound seized cars contain all sorts from lots of cash to drugs to people's whole life stories if they are moving home or used in crime, & something happens arrested etc.
A joy rider stole an MG B from a garage forecourt & got pulled for speeding, when the boot/trunk was opened the briefcase found there contained documents about evidence from a murder case & the MG owner should not have had it. The joy rider got prison so someone expressed their disapproval.
In about 1973 we sold quite a few Range Rovers, one we bought after a casual request to sell when he bought fuel & later that day I returned with him 100 miles to the owner's home to empty the contents.
It appeared he was investing in property and the rear seats & luggage area was full of layers of coats, boots, tools, documents and plans for property alterations.
It was like an archelogical excavation, 3 years of accumulated stuff.
He kept commenting how he had lost this or that but eventually everything was emptied and I made to start reversing out of his driveway when he came running after me and said he had not emptied the glove locker in the dashboard.
I'd stopped & as he leaned in and opening the locker he had reached in it and scooped out a full load of what I thought were coupons like you get for buying fuel.
It was a bundle of money probably like a small football, a lot more than the £1750 we had paid for the Range Rover. (it was 1973 & we paid what he paid for it new!)
As he flicked a note to me he said when I get a " onner" I usually stick it in here.
Driving away I wondered did he mean £1 or £100 or £1,000...... any was possible, it was a very large amount.
Another we had was a customer who had bought a new Vauxhall, he complained it had a bad smell & it had! It had been into the dealers but no solution. We made a thorough search and eventually located that something dead was in a rear chassis member. Back at the dealers they cut the chassis open to find a dead hedghog that must have crawled in & got entombed.
Usually spilt milk wrote cars off as you could never get rid of the smell.
Golf balls were another favourite for unknown body rattles having fallen into chassis legs or boot recesses & rolled around on corners or under braking.
Cars with engine changes were not unknown either, but another story.