Picture posting is enabled for all :)
I had access to a stash of pure old horse poo which I spread for the growing season last year. I grew everything, including roots, in it, and mostly all was fine. BUT for the first year ever I had white rot on my onions - whether spores had survived in the manure, I don't know, and it may have been coincidence.....check with the person who shared his secret with you, see what he uses it for.
The car should be OK. We transported 150+ bags of 4 year old cow manure & 200+ bags of rubbish from our plot The things we do for out plots ;D ;D ;D.