Having them refletched with fletchings that won't wrinkle is the only way I can thing of to keep them from wrinkling. I've seen where some people cut the whiskers out of the 3 areas that the fletching go through. To unwrinkle the fletchings, I've always turned on a stove burner to high and rotated the fletchings over the burner until they've straightened out. It doesn't take long at all, maybe 5-10 seconds when the burner is on high. Be careful not to get the fletchings too hot as it is possible they will melt.
Good luck,
-Rob