* "I polish my nails, although they're not perfect." (This is a more common and natural way to express the idea.)
* "I polish my nails, even though they're not perfect." (This emphasizes the fact that you still polish them despite their imperfections.)
* "I polish my nails, but they're not perfect." (This is a shorter and simpler option.)
Ultimately, the best way to phrase it depends on the specific tone and emphasis you want to convey.