A friend of mine found a case of old brown Grolsch bottles in a (dead?) relatives attic. They were pretty dirty and the seals were all shot, but an overnight soak in PBW and replacement seals made them look brand new. I have about a 100 green Grolsch bottles, but I'd never seen a brown one before. I assume Grolsch changed their bottles a while back and was just curious if anyone knew when they did. In the 90s? 80s? Based on the fact that the seals were turning black and crumbling apart, I'd guess these bottles had been sitting up in that attic for a while. Thanks.