I used a wad of proofide , and warmed the saddle in the Oven.. [100F]
it soaks up the waxes, liquified , like a sponge.. that was 30+ years ago.

I too use a couple layers of plastic bags over the saddle .

Long Bike tours of UK, and Ireland, I left the poly bags on at night, camping,
And
when I was wearing my rain over-trousers.
Wet tour, It stayed on for weeks.