Kevlar invisble thread is stronger than traditional nylon invisible thread.  Strips easily too!  Use it for the floating bill, the Hummer Card, and all other lightweight levitations.

Interesting History:  Kevlar is the registered trademark for para-aramid fiber.  It was developed in 1965 by Stephanie Kwolek (1923-2014) working at DuPont.  Kevlar is used as a material in tennis rackets, skis, boats, airplanes, ropes, cables, tires, and bullet-proof vests.