This is what i would suggest as well. I did some "rewrites" in my carreer and they only really went well when i worked long enough with the legacy code before.

This is what i would suggest as well. I did some "rewrites" in my carreer and they only really went well when i worked long enough with the legacy code before. Essentially getting a feeling for what it really does, being that with tests (preferred) or by reading the same lines again and again while introducing new features/bugs. If you feel the code is messy it is likely you are missing some essential business logic as well when blindly rebuilding it.