my dad's got this nasty resin kind of contamination on his hood.

http://img145.imageshack.us/img145/4263/harsem5.jpg

how should i remove this? will claying do the trick?

I would try the following. Build up the area around the blob with painters tape to get kind of a "dam affect". If it is on a sloped surface place a rag on the bottom to catch any run down of fluid. Then I'd try Iso Alc on the blob of material and let it soften up. Let it dwell for a while to work in the substance. If it softens up, gently wipe it off then buff and seal the area. If Iso Alc soesn't work try WD-40 the same way. Just try not to get that stuff on larger areas of your paint surface outside of the affected area. If there are small traces of material left you can easily clay those off.

My opposition to claying this stuff first is the potential for your clay to grab chunks of this stuff and marr your clearcoat well beyond the affected spot. I save clay for what might be left in smaller quantities that clay will grab and remove.

I suggest this because I've tried it before on stuff that looked like a resin or gum type substance and it worked great. The problem I encountered was the owner nor I knew what the stuff was but it did respond to this "softening" and "wipe" approach. Plus this approach is less abrasive to it and the surrounding area.

Good luck and let us know.

Ok i got it off the way you described but used valma resin remover instead. worked like a charm, a slight dabbing and i got it completely off in about 5 mins. washed the car afterwards, left no marks behind.:buttrock

Awesome.