Or if you can find them, a chunk of material from panty hose/nylons strapped over the venturi with whatever you can find - soft wire, skinny zip-tie, o-ring. Rubber bands will dissolve pretty quickly.
As noted, after my club moved decades ago, and there was no danger from blowing sand in the pits at the new field, those that used them stopped, with no ill effects over the years. A good idea, but the general level of risk is lower on the scale that a host of other things that could hurt an engine, unless you fly from a dust bowl type location.