SteveB wrote:

I guess we come from different parts of the country. I have seen where
a crowbar, sandblaster, and muriatic acid would be laughed off.

Same here, but that's usually because the only end of season maintenance is to
insert the damper plate and maybe throw a canvas cover over the unit. The
following spring they might put in new pads every other year.

If you do the correct maintenance every fall shutdown and replace the pads every
spring, you don't get that kind of buildup. People want maintenace free swamp
coolers and there ain't no such thing.