Shrink Firefox files:

By using sqlite3, you can manage your places.sqlite file.
Note  LOGINNAME is your windows login name
and PROFILENAME  is the profile you wish to edit. But first zip or copy  the profile folder incase you wish to revert backto

save to a batch file then create a shortcut to run again:

sqlite3 "C:\Documents and Settings\LOGINNAME\Application Data\Mozilla\Firefox\Profiles\PROFILENAME.default\places.sqlite" "delete from moz_places where  id < ( select max (id) -  (select count(id)/12 from moz_places)  from moz_places)"
sqlite3 "C:\Documents and Settings\LOGINNAME\Application Data\Mozilla\Firefox\Profiles\PROFILENAME.default\places.sqlite" "delete from moz_historyvisits where  visit_date < ( select max (visit_date) -  (select (max(visit_date) - min(visit_date))/8 from moz_historyvisits)  from moz_historyvisits)"
sqlite3 "C:\Documents and Settings\LOGINNAME\Application Data\Mozilla\Firefox\Profiles\PROFILENAME.default\places.sqlite" "vacuum;"
sqlite3 "C:\Documents and Settings\LOGINNAME\Application Data\Mozilla\Firefox\Profiles\PROFILENAME.default\places.sqlite" "REINDEX;"


get sqlite3 from http://www.sqlite.org/download.html


other firefox files:

sqlite3 "C:\Documents and Settings\LOGINNAME\Application Data\Mozilla\Firefox\Profiles\PROFILENAME.default\urlclassifier3.sqlite" "delete from moz_classifier where id < (select max(id) - (select count()*0.5 from moz_classifier) from moz_classifier);"
sqlite3 "C:\Documents and Settings\LOGINNAME\Application Data\Mozilla\Firefox\Profiles\PROFILENAME.default\urlclassifier3.sqlite" "vacuum;"
sqlite3 "C:\Documents and Settings\LOGINNAME\Application Data\Mozilla\Firefox\Profiles\PROFILENAME.default\urlclassifier3.sqlite" "REINDEX;"

to experiment with more tables in the files or other files,  use sqlitestudio   found at http://sqlitestudio.pl/?act=about