Like a few said "watch out for chemicals and old shit in the soil" Thats it. Other then the horrible things found in the ground, soil is soil. Some is clay , some is loam , some is blah blah. Mix it like a company would make their bags and use it. (plenty of perlite , organic matter, ewc, compost ect....)
Besides the bad shit in the ground we would need a lab to test for , the rest is almost seeable/smellable. The better area you get it from the more diverse the soil food web will be also. "ALMOST" every bug in the garden is good. The more life the better. If you see 4 species of bugs or more when digging one singel hole , then your into black gold. PLUS if you see 4-10 species of bugs in the soil then there is a very good chance there is no chems or junk in the soil.