Kermit

Bubble plastic and newspaper both give off quite large (relatively) amounts of acid and toxins that can harm your comic books. I wouldn't advise using either as a long term storage solution.

Thanks for the advice.

But those "products" aren't in direct contact with the bagged/boaded comics. Usually there's around 3 or 4 backboards to prevent any bent/crease on the spine of the last comic in contact with the boards/newspapers/bubbles plastic.

either air bubble plastic or even wrapped pages of newspapers in homogenic volumes do the trick very well...