This is a rough idea of how to do it, I'm not sure if the "clear list on Monday" function works though.
Code:
On *:TEXT:mypassword &:?: {
If ($2 isnum) { writeini -n Passwordlist.ini Passwords $Nick $2 }
}
On *:TEXT:!ID:?: { play -tPasswords $Nick Passwordlist.ini }
On *:START: {
If ($Day == Monday) {
If (!%Passwordclear) {
remini Passwordlist.ini Passwords
set %Passwordclear Yes
}
}
Else { unset %Passwordclear }
}