OK, now... let's not go crazy.... It's a legitimate, legal herbicide that is used on crops such as corn... applied at or below the label rate and in accordance with label directions, it behaves as advertised. And, that statement is it controls:
Annual grasses and broadleaf
weeds. Partial control of
seedling johnsongrass,
shattercane and volunteer
sorghum.
It's used in corn fields in the black land area here in central Texas. I'm a licensed pesticide applicator (actually do it only on my own property).
I haven't had a chance to look at your profile, j.meyers, but there are surely some fence lines or places where you wish to control such plants. This would be the place to spray the remainder of the material you have. It may not actually control any of the target species because the strength is unknown, but at least it is distributed and not dumped, existing strength, in one place or into a water source or waterway.
Then, the prescribed method is to triple rinse the container....so, you could fill it several times, realizing that the strength of remaining solution is now greatly diluted, and go back over the same areas. Do this 3 times and you will have the tank as clean as you will realistically be able to get it.
If the material was going to kill trees, then I would be seeing dead trees all along the fences where corn is planted... doesn't happen... instead, the fence rows grow up in robust trees of various kinds because of seeds being distributed by birds sitting on the wires.
Now, your fruit trees are newly planted... so not fruit bearing this year, perhaps not for a number of years. I believe you could use the well rinsed tank for watering them ... and believe that the benefit of the water applied with judicious timing, is better for the trees than letting them struggle without water. It will be years before you consume the fruit and the amount of herbicide remaining at that time will be truly infinitismal.
After all, it is applied to corn, which produces a veggy that we all eat... and is fed to cattle and poultry and hogs and....
So, we are now down to the personal beliefs you hold regarding "organic" food for yourself and others. If you are an "organic" believer, you have your answer since any chemical is forbidden. If not, then your pocket book controls what you do.... it's always possible to purchase a new tank..... but I don't think it's critical you do so.
You can see in the posts above that numerous others have opinions ranging from RUN to mine....
