Things You'll Need
Hand-held clothing steamer
Polyurethane foam, or poly-foam, serves both the professional and amateur when it comes to costumes. Poly-foam is strong and flexible. It offers costume creators a wide range of choices, shapes and movement. Even though poly-foam is durable, it must be handled with care when removing wrinkles from costumes.
Remove your outfit from its packaging or storage container and take a good look at it to see what parts need attention. Each type of wrinkling calls for a specific treatment. If wrinkles are merely fold lines, you might be able to get away with unfolding and waiting a few hours to see if the lines resolve. Deeper wrinkles will require general steam treatment. Heavy creases or extensive wrinkling call for targeted, heated wrinkle removal. Planning out your wrinkle treatments give the most satisfying and quick results.
Apply steam to your poly-foam garment and large accessories. Set aside very small accessories, like detachable flowers, masks, finger coverings or head bands for the next step. After you've determined the level of heat treatment needed for your costume, put it on a clothes hanger. Larger costume accessories like foot wear, hats, wings or collars are easily attached to a hanger with clothes pins. Hang the outfit up near, but not in, your bathroom's shower. Close the door, and run the shower on full hot water for about five to ten minutes. The steam, with its moisture and heat from the shower will accumulate and soften the shallow wrinkles from your costume.
For deeper wrinkles that aren't removed by shower steaming, use a hand-held clothing steamer to target specific creases and folds. Use care to not burn your costume, since the steam is hot and poly-foam can warp and be destroyed by overheating. You can also use the steamer to reinforce the creases you do want, like those separating wings, folds in pleated skirts or on the fronts of pant legs. Allow pieces to cool down and dry out before wearing or storing.
Remove wrinkles from small accessories. Some tiny accessories, like headbands or masks, might be damaged by hanging with clothes pins. Fill a tea kettle with tap water, heat to boiling, and using tongs (to keep your skin protected), gently grip the accessories and hold them in the steam. Just as with the larger pieces, you can use this steam to get out the wrinkles you do want and to reinforce the folds you do desire.
If you are going to store your costume, prevent further wrinkles by gently rolling, not folding, the pieces. Rectangular big plastic or rubber storage bins work well for long term storage. If you prefer to hang your costume for storage, prevent hanger creases by draping tissue paper or newspaper between the hanger and the garment.
Leave the bathroom while your costume steams from the shower. The amount of steam combined with the warm plastic smells of the poly-foam can be dizzying.