As I was archiving my stuff, I found that my Firefox (Portable) profile folder is over 100 mb, mostly because of 2 files: urlclassifier3.sqlite (>30mb) and places.sqlite (>20mb).
The first one is just a local database of bad/phishing/etc. sites, it's more or less not needed, ffox will rebuild it if you delete it.
The second one, places.sqlite contains important stuff (bookmarks, history etc.), but it can become unnecessary bloated over the time even if it doesn't contain much data.
First I cleared history (guess it made it a bit smaller on the inside).
Then I found that there's a tool called sqlite3 that can clean it up and make it smaller.
And it goes a little something like this:
Download zip, then extract sqlite3.exe your <profile> folder where places.sqlite file is.
Open command prompt and type:
sqlite3 places.sqlite vacuumAfter it's done, the 30+ mb file shrunk to 500 kb and my Firefox starts up about 5 times faster (well, obviously, 'cause it has less data to process).
I hope people out there will find this useful.
:arrow: Standard disclaimer: don't blame me if you break something
I can only show you the door. You're the one that has to walk through it.