How to delete an unused string resource for all configurations in Android Studio?

I've found an unused string resource, like:

<string name="obsoletestring">my name is null!</string>

However it is in tens of files, of different languages, in different strings.xml files in values, values-af, values-be, etc folders.

I must have missed something not to know any way to do this in Android Studio other than modifying it by hand one by one.

tl;dr How to delete an unused string resource for all configurations?

It is now possible inside Android Studio. After Lint checks you see an option on the right Remove All Unused Resources!

To Delete a single string resource across all locale files, you can use the "Translation Editor". 1. Right click on the res directory to open the translation editor. 2. Select "Show All Keys" selector, and choose "Filter by Text". Supply the name of the resource that you want to delete. 3. Select the resource, and click on the "-" button