There is a seltzer bottle that I want to buy off of ebay. The only problem is the inside glass looks sick. For those of you with experience with seltzers does the inside glass normally get sick/etched over time from the leftover contents? .....Or is this normally just residue that can be cleaned with a good scrubbing with a bottle brush and the right chemicals and soap? I'm just wondering if I am going to have to get this bottle tumbled if I buy it?