I have noticed that after a few batches i was getting less then perfect carbonation.
besides the hoegaarden bottles I never could get a perfect seal so headed out to the home hardware shop and picked up a high heat hot glue gun with a refill pack of 24 sticks.
During my last bottling batch I would clamp the top down then sit the bottles to the side. next i would plug in my hot glue gun. switch it to high heat and wait for the glue to start to come out of the end.
next i would glue the entire lid on by squeezing glue into the space between the lid and the glass making a nice air proof lid.
Man did this work. Every bottle now has high carb with a beautiful huge head and a sweet taste that only a good carb can get you.
I was also concerned when I used a bottle opener to open the bottle that the glue would go in.. nope the glue just peals off like a orange and you can hear a nice hiss when you open the bottle.
Best thing is since the glue never touches the inside of the bottle but only is treated as a extra sealer there is no worries of any contamination ( yeah like heating non toxic glue to 180 will not kill everything and anything on it lol )
I HIGHLY recommend everyone do this if you notice semi flat beer with no head
even if you want to just test it on 1 bottle in your next batch you will see a huge diff as I did