I understnd what you're saying. There's times you need something smaller than a 3/4 chip throw-away and use flux brushes. For really small jobs I use Q-tips. they start comming apart but will spread out epoxy for a small job. For the flux bursh type of job I will sometimes clean it in the tinest amount of thinner in a tuna can. It literally takes about 20 seconds. If I have a few in stock, I heave them because epoxy and chemicals are the least enjoyable part of boat building. Last time I got those they were 20 cents. I pays to buy a lot and make your building experience more enjoyable.

There's a discount store near me where I can get 3/4" chip throw-aways for 39 cents. I never clean those.

One time in a pinch, I chopped up a paint roller (cheap furry one) and used a 2" wide, half piece held in my hand to apply epoxy. Actually it worked pretty good.