another problem reported is that on some colors of fabric they bleach out the color slightly.

Use it all the time have had no problems with it and find it an economical way to marking quilts when needed.

If you launder after ironing marks dont reappear

I have bought some and have not used them yet. Thanks for all the information about what and what not to do.

I bought a few last week and did tests. I wrote on 3 different types of fabrics. I let the ink set for about 3 hours then pressed with a very warm iron. I found I needed to use a very hot iron. So if your fabric cannot withstand a hot iron, another "heat" source is needed. I then took the fabrics and put them in the freezer. The ink did return, but not as bright. I then washed the fabrics with warm water and detergent. I dried one sample in the dryer and the other by laying out the fabric. I did not try washing in cold water(oops, I forgot), so I cannot give a honest answer if the ink comes out in cold water. After both fabrics where dry, I put them back in the freezer to see if the ink returns.
i could not see any residual color from the pens. The satin had a faint mark, almost as if the pen point left a scar. The cotton and the poly-cotton both were clear.
I would absolutely test your fabrics first. But for myself, I was pleased with the results.

A BIG THANK YOU TO ALL WHO HAVE RESPONDED. I think I will invest in at least one of these. I do wish there was a white, but a pink might work for darker fabrics. I will probably get a pink and black. I will test on fabric first and then if my iron doesn't get out the ink, I'll put it in the dryer. I usually work with just cotton.......but I do use a poly batt in many cases......

When you iron, use a steam iron and hold it over the mark on fabric, don't lay iron upon the fabric or it could leave a slight mark.

HI use them quite a lot, HOWEVER, I did have one bag where the red pen did not go away when I ironed it...is in the lining and doesn't show, but I can see it! And on some dark purple handles I used the red one (again) on I have a white line left after ironing. I am going to try washing....again it's on the underside and really isn't major, but there!

I have had no trouble at all with the blue, black, or yellow. Just red and me have a thing!

I always use steam to remove and haven't had the mark return. I love them!!!!

I found a three pack-black, red, blue- at Office Max for under $6.00. Local quilt shop was almost double the cost. Would like to find a light color, maybe I will spend a few extra pennies for one pen I want.