Advice sought on shelf liners/acid-free boards to line pine bookcases

I have just bought pine bookcases -- which I have to line because unsealed wood can release organic acidic vapours on contact with books/slipcases (pine and oak are apparently the "worst" woods in this respect). I know that a sealer like polyurethane merely slows (rather than prevents) acid problems, so that is not an option. Felt is a possibility, but I would rather go for acid-free matte boards or acid-free clear lining (which would look better). What brands/type do you guys recommend? Thanks in advance.

What do you guys think of the idea of lining shelves with linen/cotton book cloth with paper liner? It wouldn't be the cheapest option, but the "metaness" appeals to me -- as does the color selection, which would allow me to color code my shelves. Do you think that the paper liner and cloth would be a sufficient barrier to the acidity of the unsealed pine?

See here for the product I'm considering:

www.gaylord.com/Preservation/Book-%26-Pamphlet-Preservation/Repair-Tools-%26-Supplies/Tape/Canapetta-Linen-Cotton-Book-Cloth-with-Paper-Liner/p/52160

I've never considered this problem because my bookshelves have always been painted.

I have just responded to your same question on the Fine Press forum as follows:

"I have not done lining like this myself on my book shelves, but the option that you are considering looks fine to me, with a couple of questions. I am not sure how easy this lining will be to clean, as normal dusting/slightly wet wiping of shelves might not work on it. Would it accumulate dust more easily, especially behind the books?
Another thing to check would be how soft the cloth is on the surface where you would place your books. You will be sliding your books out of shelves and back in place, so, if the cloth is on a rough side, I would imagine that it might potentially damage your bindings/slipcases.

In sense of ease of cleaning and safety of sliding of books, maybe usual plastic shelf liners that people use in their kitchen cabinets, etc. are easier and safer option.
I hope this helps..."

Thanks. After much deliberation, I took the advice of a salesperson at Talas: MarvelSeal 360 (as Jayked recommended in the Folio Devotees group) secured to the wood by 3M 415 tape double-sided. FedEx will get these to me quickly, so I should have the new bookcases set up by Sunday.

An alternative good option was Heritage Archival Corrugated Board e-flute. MarvelSeal 360 under Heritage Archival Corrugated Board liners would give extra protection, but the combo is not so affordable when you have as many shelves as I now do!

FoamCore board gradually collapses, I was told, so I ruled that out.

I abandoned the idea of lining the shelves with book cloth (which I thought would be a witty and attractive touch) for several reasons. First, after costing it I realized I could buy a Folio LE for the price. Secondly, the Talas salesperson said the cloth would provide only negligible extra protection. Thirdly, as booksforreading pointed out, the fabric would make dust removal harder (dust would accumulate more easily and would be harder to sweep away) and could scratch the base of slipcases.