Hi Zia. You cannot throw the furniture in the trash. You can however sell it by dragging it outside the front gate.

You can also store old furniture in the Decorate Tray, it expands.

There's alot of helpful information in the Virtual Families 2 for iOS forum that also applies to VF2 Desktop. Please be aware that the Windows/Mac versions do not have In-App Purchases (Lucky Rock, Food Club, etc).