so far, so good. I ran down some soda and vinegar and a little drain-o type stuff (just in case there was a clog). I haven't noticed a smell since.

I usually put a lemon or a lime down in the sink where the garbage disposor is and turn it on every now and then. We never put food scraps down the sink cause we need new pipes and all that. However, the lemon does freshing it up. I will have to try the soda and vinegar.

I just put in a new garbage disposal and I noticed a smell not long after so I started doing the bleach thing, too, and it works. I also dump a box of baking soda down there every couple of weeks and let it sit for a while. But I've also started grinding up my orange peels and lemon peels in there and it makes the kitchen smell fabulous. Hint: Cut the orange peels is smallish pieces as you put them down the disposal. Sometimes the bigger pieces jam and you have to reach down in there to get them loose - yuck!

DW is a cleaning freak. It's a hobby of hers, and actually was part of her career at one time. Her TNT is bleach for sure, but also Baking Soda followed with white vinegar. The foam will drift down and touch all the walls of the pipe. The vinegar is acidic and cleans, and the baking soda cleans and scours as well.

For a new run, she likes hot water and bleach, and for maintenance, she likes the foaming power of baking soda and vinegar. Use a trickle of hot water to push the foam down, and once done, lots of hot water to flush.

Perhaps I should relate a story here that happened to me a while back so you can check, especially if you recently had work done on your sinks plumbing:

Make sure the trap is still there! My Aunt had a friend do some pipe work for her and he basically made the drain pipes go straight (he took out that little U shape in the pipe). The trap keeps some water in the pipe, which in turn creates a seal between your air, and the pipe/septic. If there is no water there, you could get gas coming back from your sewer/septic.

If you do have a trap, make sure it isn't leaking all the water out too as this could also lead to gases coming back up.