Mazda Miata: Weak Stream?

The stream of fluid from one of my windshield washer jets is weak (e.g.,
doesn't make it above the wiper). I think the problem is the little valve
in the hose that feeds the jet (e.g., when I switch the valves from one side
to the other, the weak stream changes sides). Problem is the dealer want
$19.80 each for these little valves. Any ideas for an alternate source or
other solution?

Thanks,

Gus (91 BRG)

Even though I had cleaned them out before I tried it again (this time using
Simple Green) and I now have a strong stream on both sides. Note that the
problem was with the non-return valve not the spray jet on the hood. The
non-return valves are easy to remove.

Gus (91 BRG)