After a few ski trips in slightly painful hire boots, I decided to buy a pair that would fit properly. After trying quite a lot of pairs, I eventually found some that fitted well all over my foot, which fit with either one thick pair of socks, or two thin ones. I've generally gone for one thick pair. For most of my current trip, they've been amazing, making skiing easier, avoiding painful feet, and keeping my feet toasty.
However, today it was a lot colder, especially on the higher runs, and my toes got very cold (almost painfully). Without buying a second pair that'd be big enough for two thick pairs of socks just for the odd very very cold day, is there anything that can be done to avoid cold feet on very cold days skiing?