said by patcat88:
Never use drain cleaner. It will burn pipes before it will burn clogs. I use a hand snake + corn oil, once the clog is free, I fill the tub with laundry detergent+ water, make a slurry, let it soak into the drain with the snake still in the drain, then rotate and pull the snake out with the laundry detergent washing the corn oil and scum on the walls of the pipe off, and getting the corn oil off the snake. Corn oil lets the snake get past 360 degrees of 2.5 in drain pipe fittings under the tub quickly.
After that it's advisable to run hot water and detergent a couple of times. Oil traps all sorts of crud and contributes to the clogs.