Compressed air and a blow gun usually work well to clear out the nozzle,
and any debris from the window washer line.

Subject: Rear window squirter
I recently noticed that my rear window squirter isn't working quite
properly. It doesn't spray the washer fluid very well and then after I
stop squirting it dribbles for a bit, only squirting up an inch or two.
It looks more like a shut off valve (if there is one) isn't working. In
any case, has anyone had this problem and is there an easy cure? Thanks
as usual.
Bill H.
88GL