I us a old metal film holder filled with carborator cleaner and soak just the screen tip.
Starts fine!
I once took one apare and there is a plastic like waffer inside to shut off the Vacuum when the engin starts.
That is the reson I just soked the tip that has the screen in it.
I wonder how many were trashed by people?
I know I bough new ones but probably have the old ones somewhere.