1) Inspect all carefully. Discard bottles with cracks and hard to remove materials like dried paint, hardened glue and concrete. Remove foreign object such as candy wrappers, cigarette buts, and soils.
2) Wash bottles in strong detergent. Use appropriate bottle brush for hard to reach corners. Rinse thoroughly by refilling with clean water repeatedly. Use a pressurized water hose to do the job fast.
Then sterilize by any of the following means:
3) Get a stainless steel stock pot. Half fill with water. Place cleaned bottles one by one. Add more water to soak all jars. Each bottle should be completely filled with water and containing no bubbles. Bring the water to boil and continue boiling for for 30 minutes to one hour. Remove using glass tongs and place in drying oven immediately.
4) Arrange bottles up-side-down on the upper part of steamer. Place enough water in bottom part. Bring to boil and let the hot steam touch glasses for 30 minutes to one hour. Remove using glass tongs and place in drying oven immediately.
5) If pressurized steam is available. Apply steam in every bottle one by one. This needs extensive machine inputs though. Then dry bottles in drying oven immediately.
6) Dry cleaned bottles well. Then expose to ultraviolet lamp for few minutes. Extreme care should be exercise when dealing with uv light. Excessive exposure might cause sunburns and skin cancer. Ask the supplier for appropriate assembly and safety precautions.
7) Soak bottles in chlorine solution, about 4mg chlorine per liter water. Allow to stand for several hours. Remove and dry in drying oven. Chlorine is a very effective disinfectant.
The 4mg/L concentration is the maximum allowable amount in drinking water according to EPA. WHO standards allow a lower limit of 2-3mg/L.
Alternatively, make a stronger chlorine solution. Soak bottles for few hours. Rinse with 4mg/L concentration to remove excessive chlorine odor then dry in drying oven immediately.
Chlorine in pure form is highly toxic. Keep away from children’s reach.
8) Dry the bottles well. Set oven at 160ºC. Place the bottles in oven up-side-down and leave for two hours. A method similar to disinfecting laboratory glasswares.
New sterile bottle caps must be procured every processing session. Reusing caps is highly discouraged.