Best material for winter?

What material to use that wont get cold during winter? My iem gets hot during use but it has some metal edges that touch the ear. Makes sharp feelings that distract. Looking for iem made out of right material for cold weather. Resin perhaps?

Where do you live?..I’m in the UK and live on a barge so winter - C morning temps are a norm and my Z1R’s are just fine…refreshing to put in but after 5 mins they’re perfect unless you’re outdoors in Alaska can’t see a problem?

Any non metal iem will do.