For the bottle, just wash it with warm soapy water, don't need to boil it. You can easily push out the air you 2 fingers when the milk bottle is full, but if it's only half-fill or less, use the back of a spoon to push the air out, it is only more convenient if there is the handle. I did not buy those bottles with handles.
Hi CHITMIMI - I didn't boil the ring, the cap even the nipples, just wash them in warm soapy water & let dry or in the dishwasher(in Canada). I used the bags to store breast milk & put them in the freezer, my daughter did not like the playtex nipples, i bought NUK nipples for her, it was very similiar to mama's nipples so she likes it. To my knowledge I didn't see any straw type thing for those milk holders, because after all the air in the bag is out, my daughter just hold the bottle straight, walk everywhere & suck directly (just like having a straw). If your baby knows how to use straw, just give your baby training cups to drink. Hope that helps, and hope you understand because I cannot type Chinese in my computer.