how long are flares good for per coast guard

found it 42 months

Until they expire - per the date stamped on the side of each one.

Yup what he said.

Just curious, what is the best way to get rid of the expired flares?

I lit mine off in the street around 4th of July last year. It was pretty cool for a short while - then later I realized that the heat from the flares melted holes in the asphalt. Don't light them off in the street around 4th of July. ...or any day for that matter.

Also beware, I bought some from Walmart or similar once and they were expired when I removed from the package. Actually, the USCG inspector discovered that during an annual inspection. I always try to view the expiration date before purchasing now.

Keep some on board because they will work long after the expiration date. Otherwise light 'em or burn them.

Give them to your local fire departments. They use them for demo's etc.

I have actually tried that, and they would not take them. Neither would water patrol. I keep a bunch of old ones on board because they do work much longer than the actual expiry date, or I light them off on the 4th of July.