cash out refinancing questions

[Virginia Radcliff]

New to the forum and new to investing, but trying to keep educating myself.  My question is probably a common one, about cash out refinancing.  My specifics...

I bought my primary residence for $310,000 in 2015, with a 15 year conventional mortgage at 3.0% interest.  I have $122,000 left on that loan.  I recently purchased a rental for $245,000, with 30% down, at 3.6% interest.  

I am wondering (1) if I should refinance my primary home.  Per my broker, I could go to a 10 year loan at 2.375%.  (2) Should I cash out what I can while I'm refinancing anyway?  I don't have an immediate need for the money.  I have a stable W2 job, no other debts beyond these mortgages, but at such low rates, seems like my money could be doing more in other places.  I do eventually plan to buy more investment properties but not immediately.  I could use that cash out to pay down the higher interest mortgage on the rental property, or simply put into my brokerage account?  Would love any advice you have. Appreciate the help.