Here is the tips how to unclogging drains

Drop a couple of alka seltzer tablets into a slow drain and follow with a vinegar chaser.
After a few minutes, rinse with hot water. Your drain will be as good as new.
Would you like another bathroom cleaning tip?
Baking soda will not only clear up clogged drains, but it will also keep them smelling fresh.
Try this: pour one half cup of salt and one cup of baking soda down the drain and let it sit overnight.
 In the morning chase it with a pot (two to three cups) of boiling water.