Bottle cap liner replacement?

[Ulophot]

Recently purchased plastic bottles came with caps with a poor excuse for a liner to seal the air out. Anyone have a good, inert replacement suggestion that will work with all standard chemistry?

Thanks.

[koraks]

I find that properly fitting plastic caps on glass bottles are pretty much airtight without an additional liner. Good enough to keep mixed c41 developer good for over 6 months at least.
Perhaps it can be kept simple?

[Joe O'Hara]

Some of the suppliers of glass bottles offer the black bakelite caps with polyethylene liners. Those are very nice. I always get a bag of them if the bottles come with caps that have the paper liners that you can't really get clean.

[cowanw]

Reusable green beer bottle white caps have plastic liners. from your U brew it.

[Gord Robinson]

When I am going to store a chemical for any length of time I put a piece of Parafilm "M" over the mouth of a bottle to keep air out and prevent any contamination from the cap. It is flexible and self-sealing lab material that you can stretch over the mouth of a bottle. piece of wax paper over the mouth of a bottle will also prevent any contamination from the cap. Parafilm is fairly cheap off the big auction site.