What is the best product to keep the kitchen sink draining properly? Also, what is the best product to open a stopped sink?
I don’t know of any reason to use any product in a kitchen sink to keep it flowing. If it is slow draining, I would remove the trap, clean it, and snake out the drain line after the trap.
The same process applies for a stopped-up sink. For a sink that may be blocked with hair – bathtub or bath sink, you can sometimes pull out the debris with a hooked wire or a small tool designed to stick in the trap and pull out the debris.
I don’t ever recommend chemicals. They don’t work well. If you fill a stopped-up trap with chemicals and it does not work – now you have to deal with the chemicals when you clean the trap – not a good think.
For a kitchen sink, you could try to pour a few gallon of boiling hot water down the drain – some folks think this may loosen cooking grease that may have accumulated.