Periodically we get requests for capacitors from the Mallory CGS series, either called out by name or identified based on the part markings on a customer’s old capacitor.
This series is a bit of an odd duck, it’s not discontinued per se, but since the manufacturer has changed hands so many times over the decades it has a lot of individually discontinued or defunct part numbers and you end up with a large number of old capacitors out there with out of date markings from a currently active series. For example many of these will use “MFD” to mark capacitance values in microfarads, while the current standard is to mark them with “uFD” or “UFD” symbols.
Generally speaking I would first check to see if a given Mallory CGS capacitor has an equivalent in Cornell Dubilier Knowles’s modern version of the CGS series. I wouldn’t necessarily expect to find a direct match, but it’s the best first step. My next stop would be the DCMC series, from the same manufacturer.