Why, were you using like 100 syringes? I use about 3 at a time... a 3ml, a 1ml, and a great big 10ml. When they wear out, I get some new ones from a ziplock under the counter.
But as I've mentioned, I'm sure that having filtered water right at the kitchen tap does make a difference for me; I can rinse my syringes very easily after each flavor. I usually fill 2 bowls of water; one of hot water, one of filtered water, and give each syringe about 3-5 flushes from each, after each flavor. It still takes barely half an hour to mix up 10 days' worth, though I "clean as I go".
Andria