Hi,
I'm doing a skinning project on a fuel tank...
I've layered up several layers of resign prior to wet sanding,
My problem is there seems to be losts of places where I cant sand deeper, that are filled with a white residue, when I wipe down with water or acetone they disapear but come straight back once the surface is dry.
I know if I layer over the residue it will just stay there oviously ruining the red/carbon effect...

How can I get rid of them?
I think that the whiteness is just the residue of the resine that has been sanded, but Im having a real problems getting rid of it so I can do more clear layers.

Its usually sanded resin in the pin holes where the weave corners are.  You need to coat with resin/lacquer and sand in between each coat to fill the holes.  It will get there but it takes time and effort.

If they go clear with water or acetone, then they will go clear with the next coat of resin too.