? dealer rustproofing or factory, how to remove Options

[rudedude]

I have an original 914/6 that is undercoated with some type of asphalt based product over the factory painted undercoat.
Does any one have a good idea for removing this asphalt product? I am scraping it off with difficulty as the original paint also gets
damaged. I have also tried brake clean and wd40 but they also damage the paint as it doesn't seem like there is much thickness
to the paint. I would like to keep the factory paint intact if I can.
Any ideas?
Thanks

[brant]

whew....
I did that once.
what a lot of work!

I think I have around 60 hours total of hand scrapping with a putty knife.
I tried all the solvents without any sucess.
finally just tried about 4 putty knifes until I found one that was the right combo of flexible yet sturdy.

turns out that a stainless steel putty knife from home depot was the best in my opinion. About half way through I dulled or wore out the putty knife. Had to buy a 2nd one.....

I did it one day at a time over about 5 weekends.
Lots of blisters to prove my diligence.
some damage to the paint too.

this picture is not the best... but I didn't take good pictures of the underside of the floor pan where it showed the best. I ended up repainting the wheel wells: