These are so hard to find! They make terrific marmalade, but this year they went into orange gin (shave off the peels (without the pith) and add peels to gin in a big Mason jar, along with a couple of handfuls of rock sugar; shake daily until the sugar dissolves, then put the jar away where you won't be tempted & wait at least two years. Supposedly you can wrap up the jar securely and drive around with it in your trunk, to speed up the infusion - no idea if that works!).
The insides of the Sevilles can be juiced; freeze the juice and use in marinades. And every year I regret not buying more.