I use them all the time. You cannot use on satin or it will leave a mark. It's like a scar. But I always try on a sample first. But I live them.

I know a few well known quilters who vendor at quilt shows and they have stopped carry them.

I played around quite a bit with this pen...hoping to find SOMETHING that i can see eaisily...just love it...however I don't use it on gift quilts...never know when the quilt will get left in a car or moved across country in the dead of winter..those lines will return.
I have read that if you use starch the lines don't wash out, otherwise they do wash out so for now I use the pen for marking in the margins only.

Use them all the time. Apparently after you wash the quilt they will not come back. They do come backwhen cold but as I said washing is supposed to solve that one. haven't tried the steam idea.

Frixion Ink is PERMANENT
 

Yes, it becomes "transparent" when ironed but nevertheless, the ink is still "there" and NOTHING AND I DO MEAN NOTHING will remove it. On the label I placed on a king size DWR marked with the Frixion pen, I clearly stated that if / when the marks return to remove them with a hot iron. Any exposure to freezing cold will cause the marks to re-appear. The pen does make very clear lines but just "be warned."

If you don't do any pressing on the marks during the construction of your quilt, stain removers will remove most of the markings. Unfortunately, we have to "press" as we go and this causes the Frixion ink to become PERMANENT.

Again, "Be warned."

Yeah, sister! Once I figured out (from reading it on here!) how to make the ink disappear (ironing) I do use them. I especially like them because they have a fine point, something I've found with no other product. Also, sometimes chalk just won't come out!

I have used the pens for months now and just love them. I steam them out and they have not re-appeared.

Somehow I get the feeling that your quilts are probably gorgeous. Thanks again for your advice on my Chatter Quilts, I'm about to start using those little pieces of beauty.

I love the Frixion pens. I know the objection to the lines reappearing when the quilt gets cold, but I live in a warm climate, cannot imagine every flying a quilt anywhere and certainly don't plan to keep one in the refrigerator or freezer. You will need to use your own judment about the quilt you make. froggyintexas

My favorite markers are the Crayola washable ones. Very inexpensive and comes right out