Hi, Van. The sludge is probably hair combined with some soap residue and softened by the drain cleaner. Your auger should have something like a spring on the working end. When you put it in the pipe and turn it, the spring should screw itself into the hair clog. When you feel this happening, pull what you can out. Keep doing this until all the gunk is out of the pipe. Only then will your pipe work right. If you just keep mashing the auger into the clog, it will pack it in tighter. This will be messy as the black sludge will get everywhere.