5 down vote
I use a combination of:
iii) Hot Water
iv) Dish Soap
Over time, drains do begin to smell. There may be nothing blocking the drain, just some month old grease residue and remnants of the rest of the stuff that tends to go down the drain.
Mix about 1/2 gallon of it together, with the following quantities:
1 cup vinegar
1/2 cup table salt (not coarse!!)
Enough soap to make it “sudsy”
Pour it down the drain and let it sit in the trap for 10 – 15 minutes, then flush with more hot water.
I do that about once / monthly and it keeps the odor down rather well.
share and improve if i am wrong with the answer