After I've cleaned out my sink*, I give it a rub down with the orange peel. Then I break it into tiny chunks and grind it in my garbage disposal. I toss just a few chunks in at a time...sometimes I keep part of the peel on the sink to use again in the next day or so. Keeps it clean and fresh smelling! Lemon peel works well too, but we have orange peel on hand more often.
*That scotch brite scrubber works wonders on dishes and the sink- I got it for a couple bucks at Walmart. We have calphalon pans and it cleans them well without scratching them. I toss it in the dishwasher whenever I run it to help keep it clean.
I hate doing the dishes but these things help a bit!