Is it a "never been used" brush, or one that's just sat for a long time?
If it's new, contact Badger and ask them what to do.
If it's been used, but has sat for a long time, follow Ben's instructions. Assuming it has teflon seals, take it apart completely, and soak the parts in clean acetone overnight.
If it doesn't have teflon seals (verify that with Badger if you don't have the original packaging) then don't use acetone. Try paint thinner.
Every once in a while, when my brushes won't spray paint, I clean the tip with a soft brush dipped in acetone, remove the needle, and clean it, put it back in but not tight, and backflush with acetone. I also loosen up the nozzle parts a little and backflush with acetone.
If they still won't spray right, I take them apart and give them a "Ben Bath" in acetone.
I clean my brushes really well after each paint session, using a spray bottle to get all the paint residue out of the bowl (over a tupperware cleanout bowl), backflush with water, then windex, then a water/one drop of dishwashing solution, and I run the needle in and out to make sure all the paint is cleaned out of the barrel.
It takes me a minute+ to do that.
I have a larger tupperware filled with clean water next to my paint station, sitting on a small towel, and a smaller cleanout tupperware there, too, so I don't put the dirty water back into the clean.
My soft, cheap artist's brushes with plastic handles are always soaking in the clean water, ready to use, so I'm never tempted to skip a step in my cleaning routine.
Developing a good, quick cleaning routine that is second nature to you is a real key to successful painting, so you don't have to spend your time getting old paint out of the brush, and can concentrate on getting new paint onto your lures.