I need some help figuring out why there are white spots on a walnut desk top.  I am using an oil/turp/varnish mix – flood and wipe.  I use Tried and True linseed oil, real turpentine, and fast dry poly. 

The original finish was Tried and True Varnish oil.  It never dried and had spots all over.  I stripped it off and refinished with good results except for one area.  I stripped that that area and have put on two coats without problems.  Today I put on a third coat and found spots in both the newly refinished area and that which has been fine for two months!  GRRR!

I have two suspicions: 1)the blanket I cover the desk with is contaminated on one side (hence, I only have problems when that side is touching the work), 2) the finish is contaminated (but I don’t notice problems in my other work-perhaps because I usually use lighter woods.)

Any ideas on what the contaminate is or what else might be going on?  Maybe I need new glasses.