ancient TAGS references to deleted files remain in memory

[Benjamin Rutt]

I rebuild my TAGS files often (like 3 times per hour) via

    find /some/projectdir -name "*.c" -o "*.cpp" -o "*.h"

I have two of these files in tags-table-list.  By updating TAGS files
often, new methods, variables, etc. that I add in my code are
frequently picked up automatically by the time I want to visit them
with M-. or M-x tags-search.

However, sometimes, I delete files from my project directories, yet
the TAGS file must still somehow contain some entries in memory that
reference these deleted files.  I get errors like the following during
M-x tags-search:

Opening input file: no such file or directory, 
/some/projectdir/STORM/quality/system/stormtestbinaryds.cpp

where the mentioned filename is one I had deleted.

I know I can restart my emacs to get rid of these warnings, but I like
to leave emacs running for at least a week if not a month.  I've also
tried M-x tags-reset-tags-tables followed by M-x visit-tags-table to a
newly built TAGS file but that doesn't help either.  Is there any
other solution to this problem other than restarting emacs?
-- 
Benjamin Rutt