A cleaning method and system that utilize an organic cleaning solvent and pressurized fluid solvent is disclosed. The security tag assembly comprises a base and at least one attachment member removably connected in an operative position on the merchandise being protected. A computer determines a heat flux value as a function of the first and second temperature signals, and computes the operating temperature of the casting rolls as a function of the heat flux value, the second temperature signal and a number of constants defined by fixed-valued operating parameters of the continuous thin strip casting process.