Test if you can soak it to slop off and scrape with dry wall sharp blade.

Additionally, the lender was a small lender who represented that this was a cut-and-dry foreclosure, and if my understanding is correct, the lender's attorney remembered physically seeing the client signing the loan documents.

Houses need to be maintained, fixed up, rehabbed (like his does)  and that it takes time & money to keep a property from becoming potting soil. ;-) The "useful life" theory.  

Quote from @Barry Ruby: @Mike Hern Hopefully the developers that build real homes have access to real wet water rather than water rights…I heard a short while ago that water was an issue in this market.It can get a little dry here.

Let it dry completely, and then repeat the process over again, as needed.

One set on the beds, one set in the cleaning closet and one set goes with the cleaners who take the dirty ones back to the dry cleaners who do a professional job of cleaning and folding.

Removing dirt can cause a foundation to shift and affect houses around you so either way, you'll probably need a soils and hydrology test. 

Also, soft soil areas tend to shift as opposed to resting on bedrock which is more stable.

I hear the past owner used to take care of the property, until he got hooked on drugs.There were a few areas noted on some of the ceilings of water staining and dry wall sag...mainly in the first floor units.

If your market has older homes, known bad soil conditions, weather events, etc etc.