If you installed from source, there may be a make uninstall command. But only if the authors thought of it. Since I see that you are using Slackware, you should check out Checkinstall
which is a truly excellent program. Checkinstall is used in place of the make install command and first creates a Slackware package from the compiled code and then installs it. The upshot is that if you need to uninstall, you can use normal Slackware tools like pkgtool or removepkg.
If all else fails, you can also just go delete the files that were installed. Check the documentation and makefile to see where stuff went.