Usually we have a few thousand dollars each year to invest after we max out these accounts (and it usually just goes into a taxable brokerage account where we use it to buy Berkshire Hathaway or Markel or some other stock that does not pay a dividend).That extra money was actually how we ended up buying this duplex - thought it might be a good way to diversify our investments.I was wondering if I could use net income from our duplex (assuming we have net income, and by net income I mean what we report to the IRS) to fund a solo 401k or some other kind of tax-advantaged plan?

. - From a big picture standpoint I'm also wondering if the EPA is going to be more and more malicious in how they go after older home's with "lead paint" and inefficiencies and what that will do to long term value and cost of ownership.

Hi Scott, I don’t know a whole lot about tax lien investing as but I have been learning a bunch about it I suggest you get yourself a copy of the 16% solution by Joel Moskowitz and then go to the tax collectors went for the county/s you are interested in and learn as much as you can.

Get an understanding of what neighborhoods they are suggesting...

I appreciate any insights or suggestions on how best to proceed.

@Carlos Ptriawan suggestion has merit.    

Next, I suggest you ask you association's Board or Manager for a copy of the association's insurance policy. 

I would suggest not trying to re-invent the wheel.

Any suggestions on zip codes and realtors?

have a wonderful and beautiful Friday BP family.