. . . I have used an entire clay bar on just the roof of my Octavia today. :wonder: Endless amounts of brown rubbish seemed to be coming off, with still some little risen specs remaining (I think they're tree sap but don't want to move). This is the first time I've clayed this part of the car and only the second 'panel' of the car I've clayed since I bought the car, the other bit being the bonnet, but that didn't have anything like this level of contamination.

Any ideas what could have caused such an incredible build up? It is clear now and has been treated to Klasse and 476s, but I have never seen so much surface contamination! The remaining odd spot of sap is bugging me a bit too . . .

I'd have probably give it a go with a mild APC solution and a good rinse to see how much went, then maybe some tar remover before attacking with the clay.

Good choice on the Klasse and 476s though

This is the first time I've clayed this part of the car and only the second 'panel' of the car I've clayed since I bought the car, the other bit being the bonnet, but that didn't have anything like this level of contamination.

I clayed my Fabia when I got it, and the worst panel was the boot. I don't think the car had ever been clayed, and a fair amount came off, although not enough to soil a whole bar (I cut it into 3, and you could still use the section I'd used).

Any ideas what could have caused such an incredible build up?

I guess the obvious one is if you think it looks like tree sap, it could have been parked under a tree?

The remaining odd spot of sap is bugging me a bit too . . .

If you want to be brave, a light press with your fingernail may remove it. Otherwise, try isopropyl alcohol, tar remover, etc...

I've found that soapy tepid water works fairly well on tree sap .