question about the little soy sauce bottle

I have some of the little soy sauce bottles, which originally came with a little matching eye-dropper thing to help put the soy sauce in. But now its been over-used and the seam at the bottom split, so there isn't any more suction in the eyedropper. I've tried using the bottles themselves to suck in the soy sauce, but they only ever get about half-full, so I end up needing to take in two bottles. I've also noticed that some bottle sets don't even come with an eye dropper. Is there a secret to filling these things that I just haven't figured out yet? :) thanks!
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