Removing sap from a laundry item involves choosing a suitable cleaner for the item, loosening the sap off the item with the cleaner and then washing the item normally. In addition to the cleaner, you need a regular laundry detergent and a soft cloth to complete this task.
A suitable cleaner depends on the fabric type and color; it may include cooking oil, rubbing alcohol, hand sanitizer and peanut butter. One way to determine the suitability of the cleaner is to apply a small amount to an inconspicuous spot on the fabric and see if the cleaner stains it. After choosing the cleaner, wet the soft cloth with it, and use the cloth to soak and wipe the sap off the fabric. For a big stain, pour the cleaner over it, and sink the cleaner into the stain with your fingers. Allow the cleaner to sit on the stain for a few minutes to break it loose.
Once the stain is loose, remove the cleaner residue from the fabric by washing the fabric in warm water using the detergent. Rinse the fabric with clean water. Examine it for any stain remnants, and repeat the process as needed until the fabric is completely free of sap. Dry the fabric to complete the process.