Ben Orenstein has written an interesting article: How much should global variables cost?.
It's basically a price-list for different kinds of technical debt, and you can use it to calculate the "cost" that each of your commits adds to your codebase. By actually putting a dollar amount on each "violation" - you can get a good, visceral feel for what you're doing.
As he points out - you can still choose whether or not to keep something (sometimes you really do need to do something that would otherwise be considered a no-no), as long as you can "afford" it.
I think it's an interesting way of looking at the problem. I'd like to see you regaining points for fixing/refactoring similar code-violations out of the project too :)