How is your crappy code affecting your customers? Is it delaying adding new features? is it affecting performance in a meaningful way? do you have scaling issues? is the code buggy?

Are your customers providing feedback on too many bugs? slowness? new features not being added fast enough?

How much is it going to cost to clean up the code? Can that time be spent on something that's going to add more value to the customer?

Also each code change you introduce adds risk/time for testing, developing, debuging, release. make sure your adding value.

If your in the code fixing something else clean it up a little bit. Otherwise it seems to me your wasting time on vanity.