Are to perish with the using (εστιν εις φθοραν τη αποχρησε). Literally, "are for perishing in the using." Φθορα (from φθειρω) is old word for decay, decomposition. Αποχρησις (from αποχραομα, 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.