I am trying to replace the bathtub drain and cannot get the old one out. It has been there for approximately 30 years. The directions said to use the handle of a pliers, but my pliers are too wide to fit the slots. Tried other tools, but it won't budge. Is there anything I can use to loosen the old one such as WD40 or what they use to loosen old bolts/nuts. Any help will be much appreciated. Thank you.