Remediation of materials contaminated with a radioactive material such as 137Cs is important. Here, we report on the effectiveness of an aqueous s{line below}odium metasilicate prepared with a m{line below}icrobubble c{line below}rushing process (SMC) for the removal of radioactive 137Cs from granule conglomerates and nonwoven cloth. A 137Cs removal ratio of 78% was achieved for the nonwoven cloth sample, and multiple washings at low SMC concentrations were effective. In addition, the volume of the waste solution could be reduced by neutralizing the SMC and using gelation to remove the radioactive material. The decontamination is shown to be more efficient than that with sodium hydroxide, even for washing granule conglomerates. © 2014 The Electrochemical Society.