I do this about once every other month... to the kitchen sinks, the bathroom sinks and the shower/tub drain. It is essential... especially if you have girls... hair clogs are nasty and can get very expensive if you have to have a professional come and unclog the drain, and Drain-O is such a nasty chemical and dangerous to use!!! This is quick and inexpensive! A box of washing soda will cost you about $2.00
What you will need....
1 Cup of Washing Soda (not baking soda) per drain
1 Tea Kettle/Pot full of boiling water
Not to be confused with Baking Soda... It is sometimes hard to find... Most Grocery Stores will carry it and some smaller hardware stores carry it as well. I hate WINCO... but that is the only place I can find it locally!
Pour a cup of Washing Soda in every drain... I also sprinkle some on my dish sponges...
Pour 1 whole Tea Kettle or Pot of boiling water in each drain... this is the part that is the most time consuming... waiting for the water to boil!!! If you do this as part of your regular maintenance... you will never have smelly or clogged drains! AMEN!