Help with caustic soda - bottle cleaning

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Oct 10, 2013
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I was having problem with my bottles as I described here:

Almost all of my 200 bottles had this problem and I wanted to try something drastic. I used caustic soda, around 3% concentration and 122-140F. After soaking 1-2 hours the bottles came out clean.
My problem is that I'm a bit worried about caustic soda left over inside the bottles. I have rinsed them immediately after taking out of the caustic soda solution. I left them soaking with water for an hour, drain them and refill them with water. I rinsed totally three times.
I checked the ph of the third rinse water from the bottles and it is almost identical to mh tap water (ph=7.4-7.3 and tap water Ph=7.3).

Before bottling I will sanitize them with starsan. Will starsan (acid) be able to react with any traces of caustic soda that perhaps is still in the bottles?
I was thinking of getting white vinegar and squirt in them, then rinse again and finally spray with starsan before bottling?
Any advice? Any thoughts?

I won't be using caustic soda again in the future. But it's been 3 years now that I was rinsing with just plain water after opening a bottle, let them dry and then spray them with Starsan at bottling day. But dirt accumulated inside them. I will start using PBW right after usage.

p.s. Of course I was wearing face mask, gloves and full length clothes while working near the caustic soda solution!