Muzzys reed chamber block off plates - plugging the holes?

[TwistedKestrel]

Just got my block off plates in the mail the other day, but I'm having trouble figuring out what to block off the hole in the airbox with. I'd like to put something easily removable/reversible in there. Anybody have any suggestions, or find something that magically fits?

[Hammerhead]

I used an inverted rubber vacuum plug. Just gotta get one that's big enough.

[ninja11zx]

Yes, vac plug. should be able to get one at the auto parts store.