Wear the shirt on the lug in & during the gig. Get it really hot and sweaty. Sign it. Then sell it. If you've had more than one made- bit of potting mix in a large container of water and swish around a bit. Put it in a high saline mix (2lbs salt per gallon of water) with a devilishly thin spill of diesel across the top. Throw out on you driveway until dry. Claim each is a one-off for the gig and charge 3 times more. Obviously this will require the band to wear one each during the gig. Keep clean ones for yourself during the lug and gig!!
