my kitchen sink is clogged up. whats the best thing to use in it?

unwind a wire coat hanger, and stick it down the drain.. it helps to push the grease, food or hair down that is clogging the drain

under your sink is a U shaped pipe remove it and see if it is plugged. if so simply dig it out and reinstall it

try pouring vineager with baking soda powder. it should create a sizzling sound and might be able to clear it up. it might not sound convincing, but just try it.
the smell wont be as pleasent

Use a plunger but be careful that all the chemicals you have used do not splash in your face. ( I would not suggest adding any more chemicals. They may not all combine together without some type of bad reaction. )

take u bend off and clean it you need a bowl under it to catch anything.if this doesnt work white vinegar mixed with bicarb of soda might

Ok first thing first do you have a garbage desposal? if so then it might be jammed up, now if you dont, you want to look under the sink and take off the trap, becareful becuse you used some chemicals. then take a small hand snake or drain cleaner that you can get from lowes or home depot or any hardwear store for like 10 bucks, and slowly go in do the opening on the other side of where ur removed the trap

note, dont put gress down ur drain.