Rubble
If you destroy a building Rubble remains at its place, containing some goods. Builders can collect the goods from the Rubble and put them into a warehouse, if you have enough space. However, Builders will not pick up goods from Rubble and bring it to Construction Sites or to other Buildings that accept those goods for further processing.
You can also delete the Rubble manually for aestethic reasons.
Contents
The Rubble is a refund for the building cost of the destroyed building. It contains a certain proportion of the building materials for the building. This proportion depends on the Building refund rate set by the player's choice of game mode.
You always get 100% refund if you destroy an incomplete building.
You always get 100% refund for the contents of a destroyed warehouse, pile or tank.