Undercoating removal

[jones65]

I am trying to remove undercoating from my rear outter wheel housing. One of the problems I have is the car is already painted (long story) I have removed the majority with  a needle scaler but I am not able to fit it in my wheel well to get the rest. Anyone have any luck with any other way of removing undercoating that is not to invasive so I dont damage paint with chemicals and the such.

[WkillGS]

I usually scrape off as much as possible, then remove the rest by either sandblasting or using a wire wheel on a hi-speed 4 1/2" angle grinder.
I've heard of others softening it with heat, or by soaking with solvents.
Even heard of guys freezing it with a CO2 fire extinguisher and chipping it off!