I'm trying to remove a storage item on the relay chain, specifically a futureCode entry for a parachain.

I've seen that there's an extrinsic I can call system.killStorage(keys), however I have some doubts.

How do I find the keys to use on killStorage if this is the path forward? It seems it's Vec<Bytes> (Vec<Key>).


1 Answer 1


If you have access to the polkadot-js/apps UI to your chain, you can get the keys listed in the Developer -> Chain state section. Select the entry you want as well as the params and it will also show the key for that entry. Simply copy it and you should be good to go.

An example for futureCodeHash(2000) on Rococo would be 0xcd710b30bd2eab0352ddcc26417aa194cad3324113c312669f1ac3d50722524b63f5a4efb16ffa83d0070000

See below:

Storage app with key selection

Next up you can use this value in the Developer -> Extrinsics section to remove the storage via the system.killStorage extrinsic.

It has been deployed for this type of cleanup by the Council on Kusama/Polkadot a couple of times in the past (mostly to remove old state that has moved to different locations).

As a first round, I would always suggest that you test the process against a dev chain first, unless it is something disposable.


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