How does one decline baby things from a home were drugs were done?

My father in law offered us all of my sister in law’s baby things because she lost custody of her son and now is in jail. I would normally be thrilled to receive free things but she smoked meth and did heroin in her room for months with all the baby stuff. I don’t want to take any chances plus I heard the meth can absorb into things. My father in law does not believe this and is insisting I take them to save money.

How does one nicely decline his offer?