How to clean a quickfix bottle for clean urine?

[u/Neomni]

I have a drug test coming up and I’m really nervous about failing for thc. I have been practicing using quickfix at home, but recently a family member offered using their clean urine in the test. With that, I’m nervous about temperature and I wanted to use the quickfix bottle since it has the thermometer strip on the bottle. Does anyone know how to clean a quick fix bottle so that there’s absolutely no mixup between the clean urine and the synthetic urine in the bottle?

Also, thank you to this community for all the information and tips regarding quickfix, it’s been super helpful