When I worked at a main dealer we found all sorts in cars, from bundles of cash to articles bought in Ann Summers.... a few years back we had a porsche in for tuning that had a glovebox with Knuckle dusters, a genuine police issue baton and shotgun cartridges!
Today I was changing the air filter on my 335d as part of its service and found a dead wasps nest covering half of the filter element and lots of crumbly wasps, has probaly been in there for at least a year!