A Halon (or its derivative Halotron) fire extinguisher is the only way to go with a nice car. It is an effective inert gas with no residue associated with it, mostly used for aircraft, military and ships. Halon is apparently only approved for aircraft, police and military in the UK, but Halotron may be exempt, I don't know--it would be worth checking.
The Obama crazies want to ban it here, but they have not been completely successful yet. I have one in my car--but I'm an aircraft owner and got it through that source. Halotron may be worth checking out--it is truly the way to go--very effective and no mess to clean up.
See
https://fireextinguisherdepot.com/fire-extinguishers-1/halotron-fire-extinguishers-1.html Allen
'69 4/4
