I am picky on which bottles I reuse, I like the thicker ones so I will buy a few of the better bottles for Reusing, this not only saves me money but by refilling these with tap water you get the minerals and fluoride you need for your body, because did you know that drinking bottled water ONLY, is not as healthy as you think.
I know they say not to reuse these but it's mostly because of the germs that grow inside, so I have always been a stickler for cleaning out my water bottles(any kind) and coffee or tea Travel Mugs
Here is how I do mine.
~First Get out your BLEACH~
~ Put on cleaning gloves if you have any allergies to Bleach~
Fill a 16 oz bottle with warm water & add 1/8 tsp of bleach.
Put the lid on & shake for 10 seconds.
Pour solution in to the next bottle & repeat for the rest of your bottles.
Hang these bottles upside-down on a bottle drying rack or your dish strainer to dry.
Just as long as they are able to air dry is all that matters.
Following this procedure should get you 8-10 uses out of each bottle
I also have some water bottles that I bought and I always make sure to clean these the same.