Ok - I haven't tried a pressing cloth. I have one somewhere. I'll have to have a look. If I can't find it, I'll head over to JoAnn's tomorrow. I haven't been pre-washing(anymore), so that's my next thing to try too. I have a few older pieces I pre-washed, I'll dig those out as well.
At least I'm glad I'm not alone. I'm going to a quilt show today, so I will have a close inspection of the quilts hanging up.
I hope it washes out. I'm working on Farmer's Wife also and there is one block in there that has it. I don't want to add any more rows until I know for sure it will wash out, in case I have to make a new one of those as well. I didn't seem to notice this before. I've only been quilting for 2 years (in October) though and seem to be getting fussier and fussier about my work.