I applaud your desire to reduce waste, but…
It is important to not re-use particular recyclable bottles. (Somehow magically it is fine with the original product in it [or more so, anyway], but there is an issue with re-using it.) I believe(d) confidently that the pertinent number was 1 (and possibly 2); what I have just read mentions 7, so it might be both, or it might vary by country or something. [Edit: …Or maybe it is BPA and phthalates as separate issues.]
There is a health issue. I used to believe that there is no permanent effect, but what I have just read suggests otherwise. (With apologies) I shall leave you to do a search; start by searching for “health BPA”. The chemical in question is BPA; recyclable number 1 is PETE, and what I have just read talks about polycarbonate (number 7). The first two of those three might be different issues. (I am fairly sure that there is another chemical as well, that leaches — maybe phthalate(s). [Edit: PETE is Polyethylene Terephthalate.] )
The following is the most alarming article I just found; this is not an endorsement.
You can buy a drinking bottle that is BPA-free, or you can just go with glass or metal.
According to this article…
… the substitute BHPF appears to be harmful too.
Note that washing a bottle in hot water can make the problem worse.
For these reasons, the "hack" is that there is none.