Vallejo Paint Shelf life?

I have a LOT of Vallejo Model Color and Model Air paint. They are arranged on my open shelving.

But after 6 years on my shelf. Some of the bottles started to solidify. No matter how much I stir. The pigment just wont break up anymore. Mostly the metallic are the first to gone bad. I have about 10% of my supply just gone bad. Also all my Vallejo primers in a 200ml bottles inhibit the same problem. And I have to trow them away. Anybody here expererienced this?

WOW! Kuddos on that great collection of paints and great storage system. I have only about 20 -24 bottles of Vallejo myself so my investment is nothing compared to yours. Have you tried a commercial paint shaking machines? Good luck and I hope that you can save your collection of paints.

TJS