Probably the only bet would be an oxidizer like stain magic. Probably would take several treatments, but even then...it's not certain. My mom spilled a big cup of hot coffee and I didnt clean it up for a few days. Even then, after cleaning, I think it took 5 treatments of oxidizer until it was gone.
Use a powerful Oxidizer and a correct UV light lamp (cti) sells one.
Apply oxidizer and cover with a clear plastic sheet, turn on UV lamp and place on top of stain, check every 30 minutes or every hour. Warn customer of color loss if on Nylon.
Do not use Oxidizer on natural fibers