Well I wouldn't use it at all.. it's usually used to hide things and bodge things up these days! I'd paint it and clear waxoyl over the top, or stonechip it and paint it. I know this might not be an option, but once you've put that stuff on it's a right b@stard to get it off, and it goes everywhere! Although I suppose that might be why some people like it..
As above stonechip and paint it, shutz is a good bodge coverer, when i used to restore porsche's the ammount of bodges we used to see that were covered up with a nice thick layer of shutz
Instant MOT in a tin!!!
(not that I would do/condone such practises!!!)
(ahem)