I would like to know if there is a known procedure to drop unused translated strings off the database.
Yes, there is, but it is a bit complicated:
1) generate POT files from all the modules you use (if you use only core, you can use the provided ones) using extractor.php.
2) concatenate those into one large POT file.
3) export your translations as a PO file.
4) msgmerge the POT and the PO file.
5) empty the locale_target table.
6) import the merged PO file.
I am moving this to the translation forum.
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We are talking about 4.5, right? If po files are available for all the modules already, then it is better to msgmerge them, and the core po file, then empty the translation table, and import the po file. Which is the same as importing the core and all used contrib po files one by one, but the latter is more time consuming, if you know msgmerge :)
Thank you very much for the useful procedures :)
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