Cheapest possible solder mask-like substance

[somnif]

I recently "designed" (aka copied) an SMD board and ordered a few from OSHpark. Only problem, my bottom of the barrel Eagle skills resulted in a few design quirks I'm not totally comfortable with.

My current issue is a ground via that is positioned such that it is ALMOST bridging the two pads of a resistor. There is a gap, but the via isn't masked and I am worried that my shakey hands would result in one pad or the other bridging to the via and buggering things up.

Any idea what the cheapest possible way I could mask the via is? I don't want to spend 20$ on UV curing varnish for a 2$ board (especially since I have to drop 400$ on my car on monday). Would a simple paint marker be enough to give me a little peace of mind?

On a related topic, how would one make Eagle mask over vias?

[alanp]

Put some solder braid on top, and very very quickly heat it up and remove it. The tricky part will be not removing components while you do it.

[davent]

Score the space between the pads with an xacto/scalpel knife, might help prevent an accidental bridge. After soldering since you already know the spot, rescore with the knife to be sure it hasn't bridged.
dave