If you get highlighter pen on fabric, such as on your clothing, then you are basically dealing with an ink stain. The ink in highlighter pens can sometimes be easy to deal with, but sometimes, the stain on your fabric from a highlighter pen can prove to be extremely stubborn. Most highlighters will be a water-based ink, and the faster you can get to the stain, the easier the fabric will be to get clean.
Gather several paper towels and lay the fabric on top of them, with the stain actually touching the paper towels.
Add plenty of water to the backside of the fabric and blot firmly with a clean cloth. Fresh highlighter pen stains will be mostly transferred from the fabric to the paper towels using this method.
Flip over the fabric and rub some liquid laundry detergent directly onto the highlighter pen stain.
Allow the laundry detergent to sit for several minutes, and then launder the fabric as you normally would. If it can’t be laundered, rinse and let the item air dry.
Blot the fabric with a cloth soaked in rubbing alcohol if you can still see the highlighter pen stain. The rubbing alcohol can help remove a more stubborn stain.
Rinse the fabric again and launder as usual.