valgrind -v --leak-check=yes --show-reachable=yes --gdb-attach=yes ../src/afkmud 9500
I stick that command inside a file called grind in the area directory. Whenever I need to check for leaks or other memory problems, I shut the mud down normally, then switch to the area dir and invoke that command. You'll need to make sure the grind command has execute permission. You'll see a bunch of stuff about it, and your usual log spam. Then as long as it encounters no issues at startup, your mud will be running inside it for awhile.
If it encounters a problem, it will offer to let you attach to GDB. Usually this is a good idea, but there are exceptions. Such as with the IMC2 client startup. It will complain about overlapping on an imcstrncpy call twice, but after that it runs fine. But if you see something like "invalid read of size 2" or whatever, then you'd want to attach because otherwise your mud is about to crash.
If you encounter no problems, and want to find leaks after running for a few hours ( or ideally days ), the just shut down the mud normally. You'll get a big long pile of output of things that are potential issues. You'll only be concerned with what it says are definitely lost. Still reachable is ok since the mud would still be able to use them.
As for a MAN page, I doubt it has one. Best bet would be to read up at the website you got it from.