The purpose of this document is to outline the suggested cleaning procedure for two kinds of o-rings used in LIGO hardware, viton o-rings and PFA encapsulated viton o-rings. These o-rings will not be used in vacuum. For a list of vacuum compatible materials & cleaning see LIGO#E960022.
version 5 has been updated to include relevant background on why these particular o-rings were chosen for use with core optics, and bake testing for the PFA encapsulated o-rings.