The last time I flew, on a domestic flight, one of my lotion or shampoo bottles leaked, presumably due to the air pressure changes. Luckily it was inside a plastic bag but I am wondering how best to prevent bottle leakage on my upcoming international flight.
Should I not fill the bottles to the top to allow for expansion like one does when freezing liquids? When packing the bottles into a plastic zip-lock bag, should I squeeze all the air out of the bag or just close it normally?
The bottles are not the original lotion or shampoo bottles but smaller plastic ones that I purchased for travel. They are not rigid but not unduly flexible either.