Buckthorn Blasters offer a great way to apply herbicide with minimal chance of spillage and leakage. Ideal for volunteers! One problem, though, is that they are quite expensive (over $10 per dauber when you factor in replacement tips and caps).
It turns out, however, that they are literally the same as bingo daubers - specifically Dab-O-Ink 4 oz. daubers. And the bingo daubers are 1/4 of the price!
The only problem is that the bingo daubers are not transparent. Consequently, I recommend that you buy at least one Buckthorn Blaster that you can use to fill the opaque daubers.