A method for providing a cured coating on a tube, comprising masking and sealing an end of the tube with a self-venting cap and plug, the cap and plug comprising a tubular member comprising a resilient material having an open end and a closed end, and having an outermost sidewall; the outermost sidewall having an interior surface having an annular ridge; the closed end having a hollow dome portion defined by an annular recess, the annular recess defining an inner sidewall with an upwardly-extending annular recess, the inner sidewall containing at least one gas venting groove terminating along the longitudinal extent of the inner sidewall, and the inner sidewall being spaced from the interior surface of the outermost sidewall of the tubular member a distance greater than the height of the inwardly-directed ridge; coating the tube with a curable coating; and curing the curable coating at an elevated temperature.