Reserved Sign Stencil On our 60 mil (1/16") ultraflex plastic. This material is extremely durable, is guaranteed to lay flat, sheds paint easily and can be cleaned and reused many times. Be sure to let the stencil sit on warm pavement for a couple minutes before painting. Generally the 4" or 6" RESERVED Stencil is used on a curb and the larger sizes are used for laying flat on pavement to mark parking lot spaces.