I just turned 40 and wife is 37 and we have 2 kids in elementary school. No debt other than our house which is worth close to $800k, owe $209k on it. Kids' college and our retirement funds are well underway. Right now we have about $175k in total cash on hand which I know is too much, and it's worth less every day. Obviously a chunk of that needs to be retained for household operations and emergency fund but what should I do with the rest of it and how much should I use? Should I take $30-40k and reduce mortgage balance or what?