I've been using hobby paints for about 15 years now, but I still have the same issue. If I don't use a bottle for a week or so, I can't get it open again. Most of the time, I use hot water to heat up it up, put on rubber gloves for a good grip, then twist. This works about 75% of the time. The other 25% I rip off a good chunk of skin like I did just now to no avail. Do you guys have any tricks you would like to share?