Custom sized mattresses can be expensive. As a result, some people take a do-it-yourself approach and cut down a regular size mattress to fit the dimensions they need to fit a nonstandard size. While their ingenuity is commendable, they need to be sure the mattress they choose to cut won’t expose them to harmful chemicals.
Keep in mind that many mattresses aren’t designed to be opened. Due to the use of fire protection that can contain fiberglass or toxic chemicals that are not too dangerous as long as they are sealed within the mattress, you should know what is in a mattress before you open it up. Know before you cut because some materials can quickly cause issues, especially lung issues, if you are exposed to them.