I have a slow draining tub, my guess is that "junk" has accumulated in the cylinder trap. I have attempted to remove the cover off the brass trap but it won't budge. I have tried spraying Liquid Wrench on it to try to loosen it up, but still did not work. I am affraid to put to much force on it in fear that I may somehow damage something. Is there a trick to remove these cylinder trap covers or do you think I should just call a plumber to do the job? I have tried the liquid plumber and draino to unclog the drain but they didn't work thanx