The Remover Tool cannot delete the map itself, other players, and, in the event that a server has prop protection enabled, other players' props as well. The Remover tool has 3 functions: Primary fire removes the object you are looking at, the secondary fire removes all objects that are connected to the object and the object itself, and reloading removes all constraints from the object you are looking at. Under 'Construction,' click 'Remover.' The game will automatically switch to the tool gun, which is now using the Remover Tool.
To select the Remover Tool, press and hold the menu key (Which is Q by default), and find the tool list on the right-hand side. The Remover Tool, also known as the Delete Tool, is a mode for the Tool Gun that allows the user to delete any entity, excluding the map itself, but can still remove map entities.