I have achieved sloe jelly. It is very purple and my kitchen is not, which counts as a success. It also tastes nice, and thus is not a total waste of time, sugar, and electricity. As an added bonus, it forced me to hunt through my fridge for extra jam jars and chuck out stuff that ought to have been chucked out some time ago. No more does the jar of out-of-date grated horseradish haunt the fridge door! On the other hand, though the colour is lovely, the texture good, and the taste has just the right hint of the ability of sloes to suck every particle of moisture from your mouth, there's no denying that ultimately wild hedgerow fruits taste pretty similar once preserved. If I do it again, I think I'll look at adding some sort of spice for additional interest.