To __ Rubber Is to Make It More Durable

This page is the CodyCross answer for the clue below from Top Secret, Group 2083, Puzzle 3 (Burn Notice).

Question is: To __ Rubber Is to Make It More Durable

and the answer is: VULCANIZE

Word Meaning:

VULCANIZE — (transitive) To treat rubber with heat and (usually) sulfur to harden it and make it more durable.

Definitions from Wiktionary.