Syntax: %bSET <channel> EXPIREBANS {ON|OFF|<time>}%b

When EXPIREBANS is enabled, channel bans will expire either
after predefined time or after selected time, if the later
had been ever specified.
Letter meanings:
w - weeks, d - days, h - hours, m - minutes, s - seconds.
Executed without any parameters, the command shows the
current state.
Examples:
/msg %C SET #MyChan EXPIREBANS ON
/msg %C SET #MyChan EXPIREBANS 1h30m
