On our last RV (06 Coachmen Mirada) we just washed them in a regular washer (cold) & line dried. They turned out just fine.
Ours had a very fine saran wrap type material surrounding the foam cushions.
It was extremely hard to remove the covers without tearing the saran type stuff.
IF you have the same stuff make sure you keep it & don’t throw it out like we did!
It is there to make getting the covers back on easier.
Without the stuff acting sort of like a dry lube, getting the covers back on was like wrestling with an octopus.
I remember when my mother putting kraft paper from a paper bag over the wax and then using a warm iron (on the paper) to draw the wax out of the fabric. She learned it from my grandmother who used the technique to remove wax from the carpets in the church.
We have tried products using Oxiclean in their products and they clean burlap. i use a product called pink Magic which was on the market some time ago on TV. It had Oxiclean in it. i used it on our devan where the dog thinks thats here scratching post and it cleaned it right up. We also use it in the wash for stains.
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Ken and Velda
Dahlgren, VA.
2008 Georgetown XL 378
2010 Ford Escape Limited