Develop

Discard any card — it doesn't need to match an industry — to remove the lowest-level tile of 1 or 2 industries (or 2 tiles of the same industry) from your Player Mat and return them to the box, consuming 1 iron for each tile removed. This doesn't place anything on the board — it clears out your lower-level tiles so your next Build of that industry uses a higher, usually more valuable, level instead. A Pottery tile showing the lightbulb icon can never be Developed; it can only leave your mat by being Built.