Make every line of code count when writing "test" code

Yeah yeah.. you're just making "temporary" changes to test something out and you'll "re-write" it if it works out. Put a bit of effort in to cleaning up any non-sense (there'll be plenty)  as you go on and try to make it look "professional" 'cos chances are that the change will become "permenant" and you won't rewrite it till the next major refactoring session.
It's something that happens in most main software development projects. The developers test things out, try to tweak the system and improve performance. When the project managers see this, they're gonna want it in every system that they have and they would want it "right now". You'll be lucky to get enough time to copy and paste you're code (if that's actually necessary). Re-writing or re-designing won't be an option. So you're "temporary" code is gonna end up in the product source. if you don't want some ass hole to dig it up a few years (or months or weeks ) later and make fun of you, make sure that you write great code no matter what you do.
It'll save you a lot of time and the chance of getting mocked by some smart ass that you don't like.