First, check the label to make sure the pajamas are treated. Most will be in the US. To get rid it, wash it, adding twice the amount of fabric softener to the wash. If you want something a little more "green"-friendly, try soaking it in an acidic solution like white vinegar or lemon juice in water. Make sure it is diluted well. Another solution is to buy t-shirts and sweatpants to wear to bed instead of pjs.