hmm; I recently had the need to find where the “temporary” PDF was stored, as a result of selecting “Print > PDF > Open in Preview”, in an app - and found that it’s no longer simply in your user’s $TMPDIR - so:

here’s a command-line to find recent ones and move them to the Trash, to review (and likely delete):

find $TMPDIR ~/Library/Containers/*/Data/tmp/TemporaryItems -type f -mtime -7 -iname \*.pdf\* -print0 | xargs -0 -r -L1 -t -I% mv -i % ~/.Trash/; open ~/.Trash/

(note: there may be several of the same name, and these will not overwrite each other, and thus not be moved - after disposing of previous results (as per your needs), run the command again. lather, rinse, repeat.)
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it appears these dirs are not cleaned up on a schedule (though may be cleared via Safe Mode), so files may linger here for quite some time - including, depending on what you “Print to PDF”, some that you may not want hanging around (ex: bank statement).
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BTW: depending what apps you use, you may want to check what else is in these TemporaryItems dirs:

find $TMPDIR ~/Library/Containers/*/Data/tmp/TemporaryItems -type f \! -name .DS_Store -ls

(as usual: caveat lector)