Nice ride today, just 3 of us. Friend got a flat and I was elected to swap the tube for her, in the interest of time. I don't mind but her rim was covered in some gritty, oily slime which got all over my hands. At least I took my gloves off first. Found the thing in the tire and had a hard time getting it out, then it disappeared. She had what looked like electrical tape as a rim strip and it had moved around and was sticking out after the tire was inflated.
My other friend and I had put our bikes in some ground cover and the sprinklers came on as the wheel was going back on the flatted bike. Stuff got wet but at least I had a chance to was some of the crud off of my hands.
Friend promised to get a new rim strip and clean the greasy stuff off the wheels.