Assuming you have various user levels doing the same command, you can use an if statement and $ulevel identifier to do it in three ways:
on *:TEXT:*clean*:#:{
if ($ulevel == clown1) || ($ulevel == clown2) || ($ulevel == clown3) {
...
on *:TEXT:*clean*:#:{
if ($istok(clown1 clown2 clown3,$ulevel,32)) {
...
on *:TEXT:*clean*:#:{
if ($regex($ulevel,/^clown[1-3]$/i)) {
...
Note that the regex example doesn't count unless you really have the same user level with 1, 2, 3...etc attached at the end.