how to remove a washed on dried on sticker from clothes?

I'd advise using hairspray. Spray it on and then rub it with a towel. Hairspray is my universal stain-and-everything-else-remover. After that, wash them to reduce the stickiness of the hairspray! :D

This is a two step process:

1. Rub oil into the back and front of the sticky parts, removing as much paper and sticky stuff as possible. Rub it well and get it dissolved as much as possible. Then blot with paper towels to remove excess oil. Re-treat if there is a lot of sticky stuff still on the fabric.

2. Get some Goop hand cleaner at Wal-Mart, if you have one near you or some other discount department store. It will be either in the auto department or near the laundry stain removers. It's cheap and comes in a tub or a tube. Tub style is easier to manage. Use no substitutions, Goop works the best. Rub some into the remaining oil/sticky remnants well and launder as your final step in this process.

It may take a little working of the fabric, but it should come out totally. The oil will dissolve the sticky and weaken it and the Goop will take out the oil, even though it may feel oily to you, trust that it is not. You may have to do the process twice depending upon how well it goes the first time around. If there is any sticky stuff remaining after the first round with oil and Goop, let them hang dry and then re-treat them with the same two step process again. If you dry the pj's in the dryer before the sticky is gone it could end up on the dryer drum walls and then you would have to clean them too. The dryer can also set stains if they are not totally washed out. Better to hang dry treated items to be sure all signs of stains are gone before using the dryer. The heat will and can "set" stains and make them nearly impossible to ever totally remove.

Soak it. My daughters done it before too.