Take a few moments every couple months to scrub out your outdoor trash cans (I do our recycling bin at the same time too). It really only takes a couple minutes. And if you store your cans in the garage as we do... its so much more pleasant if they are clean and odor free.
I use an old broom to the scrubbing. That way I don't have to reach in and get wet or dirty. In the past I have always used ammonia, but we were fresh out last night.
So I turned to my tidy wife's favorite - Simple Green.
It took all of five minutes to spray them down with the Simple Green, scrub the broom around inside and rinse with the garden hose.
I must say, the Simple Green did a marvelous job, and left the cans smelling extra fresh and clean.
Remember to tie up your bags securely and not to toss in loose garbage and your cans will stay clean longer.