Pretreat the areas where the melted Chapstick is located with heavy-duty laundry detergent. After 10 minutes, rub the stains vigorously with your hands for about 5 minutes and, according to Heloise of "Good Housekeeping" magazine, launder the pants in hot water, or the hottest water safest for the fabric -- as indicated on the pant's care label. Repeat two to three times. Do not dry in the drier until the stain is completely removed.
Remove the melted Chapstick with a degreasing hand cleanser, often sold in auto-parts or home improvement stores. Chapstick's manufacturer suggests placing a paper towel under the stained areas to catch the grease and stains. Then rub the stain vigourously with the hand cleanser for 5 minutes. Repeat with heavy-duty laundry detergent and rinse under hot water.
Place the pants on an ironing board and set a piece of white blotting paper or white paper towel on top of the stained area. Set the iron on warm or on a low letting and iron the paper. The Chapstick will transfer to the paper. Replace the paper as necessary and repeat until the Chapstick is no longer transferring to the paper. According to Chapstick, pour boiling water through the stained areas after ironing and blot the area with a dry cleaning solvent. Launder afterward, preferably in hot water.