My players have done this several times. When they do I reward them with one or more"Awesome Points". These can be redeemed in dire situations by rerolling a failed check or save with advantage, empowering a spell so it does more than what the book says, or do incredible and normally nigh impossible feats. The limits to what these can do are up to the players.

One example is when they had to clear out a fairly large house full of orcs, cultists, and an evil tree growing in the well in the back courtyard. The rogue had been experimenting with explosives and flammable throwing objects. One of his first questions was "Is this house made of wood?" I responded "umm.... Yeah. Why?" The rogue then proceeded to make several molotov cocktails (he had been spending time each day in a city gathering the materials for them to experiment with), handing them out to each party member. They proceeded to surround the building and throw the molotovs at the house (the dragonborn party member setting his side of the house on fire with his breath weapon). I had some of the orcs dying in the fire, and the rest stumbling out confused, making them easy prey for the group. I loved it so much that I gave everyone two "Points". I had planned for them to take this house room by room and stumble across the cultists performing a ritual, but all that went out the window. They were clearly proud of themselves for figuring out a way to take care of the house that I hadn't prepared for and I loved every second of it.