window clearlevel <level(s)>
The WINDOW CLEARLEVEL operation removes all items from the WINDOW LASTLOG whose output level is in the level mask. You can specify multiple levels by comma-separating them, Removing things from your lastlog also removes them from your scrollback and your screen as well. This is useful for making certin types of output go away
Example:
/window clearlevel JOINS,PARTS,QUITS
The /WINDOW CLEARLEVEL operation first appeared in EPIC5-2.1.6