I have a motorcycle helmet that has ants in it. How can I get rid of the ants without ruining the helmet?

Keep the helmet indirect sunlight that would be the natural way of getting rid of ants, else try some sprays avail at the stores

keep in sun

If you don't want to use bug spray inside your helmet, then I suggest that you put the helmet in the refrigerator because the cold may kill the ants that inhabit the helmet.
You might even put the helmet in plastic if you decide to employ this method so that the ants don't start to invade your refrigerator.

Use sugar. locae a pile of sugar next to the helmet and in a few minutes, the ants will migrate to the pile. The pile can be as far as two feet for this to work.

Put the helmet underneath your butt – spread your cheeks and start shooting logs in it – along with expelling stale gas – this will kill the ants. When you are finished make sure you mark your territory by smearing your butt on the helmet.

Sprinkle a sh*t load of baby powder in it and leave for a few hours,,no chemicals and nasty smells .This works around the house as well,,where ever ants are coming in ,,put down the powder and the ants hate it,,easy to vac up as well,and makes the house smell nice !

If you can pull the liner out of the helmet I would do that, just to make sure that the ants have not started to break it down. Ant release chemicals and they like to burrow.

Mix some sugar in a tiny bit of water and put a thin film of the mixture in a shallow saucer. Put the saucer next to the helmet. When the ants are all out of the helmet and in the saucer, hang the helmet up and clean out the saucer.

Get a powdered form ant killer at your nearest hardware store,or blow them out with air hose.

Try an ant trap. They're usually available at a feed store and maybe a garden center. Vacuum out the carcasses and wash the insides and maybe shoot some febreese in to kill odors. Good Luck!

Pitch it. It's got bugs in it. The bugs are there because they found something they considered "tasty".
Get a new helmet. You know you want a new helmet. That one has been inhabited by arthropods, for God's sake.
No one will blame you.

Smoke.

Light up a Jamacan cigar and smoke them out…you'll enjoy both the cigar and the ant-less helmet

go to a hardware store and ask to borrow their paint mixer. put your helmet in the shaker secure it then turn it on. this will give the ants brain damage and they will fall out. you should be ashamed of your self for not riding often enough to use your helmet.

If you couldn't figure this out without worldwide help, how in heaven's name did you ever get a motorcycle license?

Put it a freezer, kills the ants and doesn't damage the helmet