Lets see. I HAVE washed my NH 1920 a couple of times.. namely when I was out working in a boggy river bed, and had mud from head to toe... Have also washed it after brush cutting in 7' tall ragweed and dog fennel.. thoug I don't routinely wash it... though do wax it once I have it washed.
that is my work tractor...Now on the other hand.. the antiques I refurb.. they are a different story... Once I'm done putting them back together.. I use a soy based wax from JD, leaves a nice protective shiny finish.. easy to dust off. I also <cough> have a flannel fitted cover for at least one of my old fords.. <cough> <cough>...
Strangely enough.. thinking about it.. I haven't washed my 98 dodge.. ever... nor has it ever seen the inside of the garage save for what it can see from the driveway... whereas ALL my tractors are under some sort of shelter.. either garage or barn... Hmm... maybee I have something backwards here......
Soundguy