I use a product TREND - available many places - based on a recommendation by a user here.
it works. soaking takes minutes, not days.
can't offer an opinion if it's "the best" - not used other stuff - can only relate my satisfaction with 'it works good'
soak the bits in TREND (jar/glass/whatever) - I use a brass brush (Harbor Freight...) and Q-Tips for mechanical 'scrubbing'
bought a big flat round thing to soak/clean 10" table/RA saw blades. essential procedure if you're ripping pine/fir 'dimensional' lumber from the big box stores.
router bit or saw blade, the pitch/tar/whatever from softwoods goops up a blade and continued use fills the shop with smoke....
the heat=the smoke generated,,,, is what kills your edged tools.
also creates "forcing the work piece" situations - which is know to easily creates "oops, there's blood all over....."
so keeping your blades/bits clean in most definitely worth the couple minutes it takes.