Remove all Tags whose name starts with ...

Is there an action that can be created to entirely remove a tag if the tag name (i.e. the name of the tag itself, not the tag's content) matches a certain criteria?

I'd like to remove all visible iTunes tags (I'm not talking about the hidden embedded stuff) and seeing as they all start with the same 4 letters "ITUN" (e.g. ITUNNORM, ITUNMPB, ITUNESMEDIATYPE etc.) then creating an action that removes any tag name starting with those 4 letters would mean that I don't have to look up every possible iTunes tag name and manually list them all under the 'remove fields' function.

Also, this action could then easily be adapted for other uses, such as to remove all tags that have names starting with "ORIG" or "WWW", for example.

Any help on how to do this would be much appreciated.

There is an action type that removes tags but it does not support any wildcards. You have to enter an explicit list of field names.
if this is too much effort you can also go the other way round and supply a list of fields that should be kept, yet you have to use a different action for that "delete fields except" with the list of excepted fields.

Yes, I am aware of that it doesn't support wildcards, which is why I was hoping that there might be some work-around alternative that gave a similar result.

I am also familiar with the 'remove fields except' function, but this would mean that I'd have to spend even more time listing every possible tag that I might want to keep (which seems like overkill just to remove some iTunes tags).

Is it possible to use a variable to store the desired collection of tag names, and then make the remove function use the variable instead of a list of explicitly stated tag names?

I think the easiest way is to apply a filter first and then delete the tags.

e.g. Filter: * HAS itun

Where would you store such a variable? As you only see the fields and their contents of the currently selected files, you would have to store the data in each file as a user-defined field.
Or you start to define an action to remove the fields.
As you can edit the fields-list as often as you like, it serves more or less as a variable.

If you think the removal is necessary only once in a while, you could use the extended tags dialogue and delete every field you want to get rid of.

There is no ready made way to use wildcard tag-field names.
But there might be a way to go ...
/t/15611/1

An easy way to go is using an action "Remove fields".
Start with a list of ...
ITUNNORM;ITUNMPB;ITUNESMEDIATYPE
... if needed, in the future, add new names to the list.

DD.20150118.1959.CET

Thanks for the suggestions.