I have a pair of cream linen walts with a bad case of coffee spill. It says no washing machine, dry clean only.
What would happen if I was to clean them at 30° with low tumble dry (my machine goes as low as 400 rpm) ?
Also how do you guys clean your tweed wool rivets?
Abort. Dry clean both.
Any drying or heat at all will make the stain burn into the fabric.
And for the linen walts with the coffee stain, I'd use a dry cleaner skilled at stain removal. If you're in the U.S. and do not have a good dry cleaner near you, Fave FabriCare is supposed to be the gold standard for doing this by mail. If you're in the NYC metro area I can provide more detailed recommendations.