Are to perish with the using (estin eis phthoran tēi apochrēsei). Literally, “are for perishing in the using.” Phthora (from phtheirō) is old word for decay, decomposition. Apochrēsis (from apochraomai, to use to the full, to use up), late and rare word (in Plutarch), here only in N.T. Either locative case here or instrumental. These material things all perish in the use of them.