Is there anything useful to be done with accidentally made superior items? I still have never had to repair any of the first sets that I made, and probably won't for a while.

If you die in the wilderness I guess it drops some amount a coins (according to the Wiki), about a million in change or so. However I wouldn't recommend trying to farm that - just save it as an extra. You can combine charges on them as well into one charged version, but that's only really useful if you have two worn out sets. Probably just keep it until the first set runs out, then throw it away, as I don't think there is any way to disassemble it or anything.

You can use it as backup armour for bossing, or you might go warbands with it.

Dying with it and collecting the money (via a friend) is actually a viable option:

the normal seasinger robe top are currently 2.7m and cost 80 chi to make

the superior sea singer robe top costs 100 chi to make

if you make a normal version of the seasinger robe top and sell it, each piece of your chi used to make the robe top is worth 2.7m/80, which is 33750

if you use a superior seasinger top and break it to retrieve the convert coin value,its worth at least the value of12/10 times the normal sea singer top plus 1.8m from breaking it.1.8m/20chi makes each extra chi in making the superior sea singer robe top worth 90k.

 

overall the superior seasinger top is worth 3.24m+1.8m, which is 5.04m, or 50.4k per chi as opposed to the normal seasinger top's 33.75k

That's a great point. Hopefully jagex won't have changed this before however many years it will take me to actually use these up.