You can buy some tablets (like "medicine") from Bx Bx DreaX), the brand is Chu ChX. One pack of that brand has about 12 pieces of tablets.
Bring a big food container with lid (or a ziplock) where you can fit in your baby bottles.
Before you sleep at night, you wash the bottle, put the bottles plus teats inside the food container/ziplock, add cold water, and add that tablet. That tablet will melt. Soak the bottle overnight.
And rinse the bottle in the morning to use it! (but it smells like bit like bleach, but dont worry, rinse the bottle a few times and it's fine).