Hfree
From Scriptwiki
Frees an existing hash table.
/hfree -sw <name>
The -w switch indicates that name is a wildcard, all matching tables are freed.
Using the -s switch makes the command disply the result (e.g. * Freed hash table 'moo' (100)). The number in brackets is the N you have specified in your hmake command (100 is default).
Example
hfree users
It will just frees the hashtable called users