I just finished six layers of primer, base, and vp, all beautiful, but when I began to burnish, greyish-balck streaks appeared. these did NOT appear when I did my sample board. has anyone had this happen? The base vp was clean; I used earth pigment, a pavon trowel...I'm wondering if it was bc I didnt clean off my trowel well enough after I sanded it with my 600-grit paper. Help...

pavon trowel - is it a stainless steel trowel?

It is stainless, and my understanding is that it is high quality. That's why I'm thinking its an issue of the sandpaper having left bits of material which then fanned out as I burnished. I am sanding it; have gone over the wall with 200-ish grit and will work my way up to 1500 and will then buff. Then I'll go over the whole thing with pigmented wax. But I need to figure this out for the other three walls; yikes, I dont want to go through this sanding again...