yes you need to assign a portion of the sales price and selling costs to each separate asset (that could be zero if in your judgment the item is worthless). that's the only way you get the benefit of reducing the gain by any undepreciated cost. I'm not saying this is right but professional tax programs allowed accountants to use a provision in the program that allowed for mass disposition. thus the total sales price, total sales costs, total cost of the land, building and improvements, total depreciation were reported as a single item. Turbotax for taxpayers doesn't allow this (its pro programs did at least at some point in the past). you need to use your judgment but what the pro programs did was in effect like allocating total sales price and selling costs in relation to the original cost of each item.
