An alternative to clingfilm and plastic?

Gavin harvests resin
So far I have used cling film or shower-caps to stop bread- or pizza-dough drying out.  But I’d prefer something re-usable.  I experiment with cloth dipped in pine rosin and beeswax. Lacking any pine rosin we went off to Tornat Wood to harvest resin.

Behind me is the Urr River where we often sail.