I used to live a mile from Saltford, it's miles from the coast! It's as close to Bath as Bristol Having lived on a cliff, overlooking the estuary, I can confirm that coins tone extremely quickly if left unsealed! I bought my wife a vicky halfcrown brooch, which went from blue to black in the space of 4 SUMMER months! We were living in a caravan at the time and had the doors and windows open a lot! Breath in that fresh see air, that was our policy! I wouldn't have kept my collection in that space, though! I should perhaps add, there were probably a great deal less other pollutants in the air on that cliff, and lord knows what all of those little nasties can do to our coins?