Creating cavities to simplify and save space?

I learned SolidWorks by choosing to build a house using blueprints as a learning project. Because this was a learning project, it was not done correctly, but I am fixing it up and I would like to know if there is a better method.

Problem:

Many of my parts have been edited and reedited and contain a large amount of unintended external references, unused drawings, overlaping and irrelevant extrudes and cuts and additional appearnaces information. The house is fine the way it is, so I dont mind losing the external references.

My method:

I am taking the parts that are good from the assembly and making a mold of each to reassemble the house with clean molds. I am assuming these new parts do not contain all of the extra data within the old parts and the new assembly will no longer contain duplicate hidden parts which resulted from making copies. I am doing this by singling out parts with the finished shape, makeing a cube around the old parts, making a cavity of the old part within the cube, then making a 2nd cube part of the same size and taking a cavity from the 1st, which results in a mold of the original part. Then I'll break the external references from the final parts and delete the two parts used to make it. Then I will reassemble the house with the new molds.

Qustion:

I want to know if there is a better method to cleaning up an assembly like this and to know if this will result in significantly reducing the assembly file size.

Thanks,

Scott

SolidworksGeneral