"Toxic for 10,000 years" does not mean "get radiation exposure for standing next to unshielded waste", not does "cool" mean "non-toxic". The ionizing radiation danger of materials is inversely proportional to their half-life. Stuff that requires inches of lead generally has half-lives in the years or tens of years. Stuff with half-lives in the thousands of years can generally be "shielded" by a thick glass jar.