Abstract: A SQUID, nominally of the "hybrid" type, wherein the normally superconducting modulation coil is modified to instead be a non-superconducting material, nominally manginin, exhibits reduced long-term, or d.c., thermal response. When an alternating current waveform--rising to a nominal 130 ma. r.m.s. amplitude within a nominal 0.5 seconds and, after a nominal 100 msec. to 20 sec. duration, returning to 0 within a nominal 0.1 sec--is applied to the non-superconducting modulation coil of such a SQUID at superconducting temperature then the entire SQUID thermal response, particularly including the short-term, or a.c., SQUID thermal response, is thereafter reducible to essentially 0. The process is hypothesized to "deflux" the SQUIDs of fluxons trapped during the cool-down of superconductor within the SQUID and associated circuitry. The optimal "de-fluxing" alternating current waveform for any individual SQUID is empirically derivable.