Every time I use Butvar in acetone (10% w/v) on a fossil, I get a white milky residue that is very difficult to clean off.
I was told that the relative humidity had to be below 50% to avoid the white residue, but in Florida that does not happen that often.
Questions:
1) How can I pull off the white residue without damaging the mammal fossil (manatee skull)?
2) Will a 5-10% PVA solution in ethanol work better in a high humidity environment than Butvar?
3) Would dissolving Butvar in ethanol work better than in acetone for the white residue?
Any help is appreciated.
Thanks.
TrilobiteAndrew