I found this info online:
RE: Removing Wonder Under From Clothing
Post By speedwell (Guest Post) (11/21/2006)
Set the shirt spot-down on a clean waste cloth (cotton preferably), and iron a little longer than you did to apply the appliques in the first place. Don't overdo it, but get the area nice and hot. Repeat if necessary until the waste cloth has absorbed the excess adhesive.
To prevent lifting in future, be sure to use the minimum time recommended, let cool, and re-iron the spots necessary. Over-ironing weakens the adhesive and makes it run, which is the principle behind removing the adhesive spots.
It is possible to remove the applique but there's no guarantee you will remove all the glue. If you want to try it here's what to do:
Heat the applique back up with an iron (to re-melt the glue) and be sure to remove it while hot. This might leave a white adhesive residue when cool. If this happens try the following: Take a piece of clean cotton and place the pocket face down on it. Press a hot iron on the pocket, pressing for a bit longer than you did to adhere the applique. Peel it away from the cotton. Move the cotton over to a clean spot. Repeat until the glue has been absorbed into the cotton. (You can do this with wax too).
Removing Fused Interfacing
To remove interfacing that has been fused in place, hold a steam iron over interfacing for 5 - 10 seconds. Immediately peel off the interfacing. If it is still adhered, set the iron on the interfacing, but do not use pressure. To remove any fusing agent that remains on the fabric, cover it with a damp, lightweight fabric scrap and press. Peel off while warm. Continue with new scraps until all the adhesive can be removed by sponging the area with rubbing alcohol--but be sure the fabric or dye will not be affected.
Hope this helps,
Sondra