How about compressed air? Seems to me if you have an air compressor, you could disconnect the fluid line and see if you can push the clog out. That would be "from" the exit point.
Just a thought!
As for cleaning chems, stay away from things with ammonia, or any “alcohols” Ethanol, methanol, Isopropyl, and such. All these chems have a tendency to leach the plasticizers out of certain rubbers, vinyls, and plastics. Thus making them brittle and prone to failure. Once unclogged, just plain soap, or perhaps wiper fluid
, both will reduce the surface tension of the water, and make it clean better!
