I assume you mean an extra $160,000 sitting in some type of non-interest bearing account (or at least, not a meaningful interest rate)? The crappy interest rates really only apply if you're quite literally squirreling that money away in a typical savings account or CD (or bonds).
First, can you determine how much of that $160,000 IS for emergency use? People have varying risk tolerances, but for my family its six months of expenses in an easily-accessible checking account. Since you don't have a mortgage, it shouldn't be that much which is great.
Are you already maxing-out available tax-advantaged accounts like a 401(k) and Roth IRA? Do you have any kids (so perhaps a 529)?
How much of that $160 are you left with now?
If you're in really good shape with all of those - I do two things: 1) I do the "boring" thing and just keep plowing money into my S&P 500 mutual fund; and 2) to keep things interesting, I actively invest a small portion of my funds.
You can join an informal investment club or perhaps start a mini-club with your spouse. Do brief presentations to each other on interesting stocks to purchase and why. Maybe you want to "risk" some of your money on something cutting edge, or be safe and finally buy some stock in Apple or Coca-Cola or J&J or something. Just make sure you're OK losing this money - it cannot be part of your FIRE plans.
There are many options - the above is a reflection of my personal situation so take that for what it's worth here on the Internet.
PS - if you meant literally "$160" a month, it's actually no different. Determine how much of that per month you need for emergencies, check your tax advantaged account use and have fun with the rest.
