If a charity sends you unsolicited materials, you are free to keep the materials or dispose of them and are under no obligation to send the charity money. Charities often mail out such goodies in their direct-mail campaigns as an enticement to respond with donations, but they do this knowing that the percentage of people who will actually donate is quite small.
With religious sacramentals, an object that is blessed should not be thrown away but either burned or broken up and the ashes or fragments buried. Charities should tell you in the promotional literature if the object has been blessed. If there is no mention that the object is blessed, you are free to assume that it has not been blessed. If you are uncomfortable with disposing unblessed sacramentals, you can donate the items to a local Catholic hospital, prison apostolate, parish or diocesan ministry, or other such Catholic group that would appreciate having such materials to distribute to the needy.