If the nest is small accessable I remember somebody recommending expanding filler foam in the past (available in all ferreterias), aparently once the nest is encapsulated in this and left for a few days it can be cut away and discarded.
Although if it not in an unsightly or visable position, I think that it is generally recommended that the dead nest be left in-situ, as it is likely to be a considered a good site by another colony, and they may begin building a new one.
Engage the enemy at night though if possible, when everybody in that particular waspy casa is at home and not out foraging.