the tub/shower and sink in one of our bathrooms is semi-clogged. the water in both drains real sloooow! we have tried plunging, and liquid plumber, helps, but not a fix. i pulled the trap off the sink to have a look, it was clean. the trap is brass/crome platted and goes into what looks to be 1 1/2" - 2" pvc. if i need to rent a snake, is there a special type of snake to use for pvc? should a 1/4" snake surfice? how would i snake the tub? from the overflow? the overflow also has the open/close drain control in it...bob P.S. the sink in the other bathroom drains fine, so it must be clogged between this bathroom and the main sewer line, correct?