So on my 2005 ML350 the washer nozzles stop working all the time. I've pulled the main washer hose, backflushed it with compressed air and it keeps clogging.

When I look in the reservoir, I can see a bunch of crap in it. I've tried flushing it out with a hose over and over and the nozzles just get clogged again after a few seconds.
It looks like its leftover old blue washer fluid that has crystallized on the reservoir

I'm not sure if there is a better strategy here to clear it once and for all?

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k