As has been said a plunger is about all ther is unless you can manage a snake which never works for me. Remember though that the plunger's job is just to jiggle things till they loosen. It is not intended to push the blockage through, it's more to back it up a bit and let water pass it to hopefully break it up. You need some water above the plunger, but not so much as to cause slop when you work the plunger up and down. Not too much force on the plunger, more persistance tnan violence. Sometimes it can take several sessions over a few hours. The plungers with an extra funnell like extension that looks like it'll fit into the opening seem to do better.
I've also heard that hot water may help, if water is passing through at all. Tom Fowle
