Baking polymer clay at regular temperatures can occasionally create a smell that can irritate sensitive people. Much in the same way some perfumes give you a sore throat or headache if they're too strong. ... Covering clay during baking greatly reduces the odor.

Are polymer clay fumes toxic?

Although polymer clay fumes are not dangerously toxic, fumes at high temperatures may cause eye, nose or mouth irritation if projects get too hot in the oven.

Does polymer clay make your oven smell?

Baking polymer clay at regular temperatures can occasionally create a smell that can irritate sensitive people. Much in the same way some perfumes give you a sore throat or headache if they're too strong.