The Urban Decay liquid eyeliners have a pretty big "well" where the wand is applied so I usually have no problem just taking a standard eyeliner brush and getting some out that way.
I usually do liquid liner with a "push" brush (flat topped stiff eyeliner brush) and I just take some off with that brush from the brush applicator of the product.
Or I just use cake liner, gel liners. If you have a black mascara that is "inky" and "wet" enough, you can use that as liquid liner too with your eyeliner brush from your kit. The High Impact Mascara from Clinique is surprisingly good for this because its super black, super wet and its a tubing mascara so its a polymer that can be used as a liner in a pinch pretty easily.
hope that helps.