I was lucky enough to get some French ammo packed on stripper clips/chargers. They are shiny aluminum. I have not tried alternatives, but apparently the case head diameter is just about identical to the 7.65x54mm Belgian/Argentine/Turkish Mauser cartridge and the 6.5x55mm Swedish cartridge. You might try some Swedish 6.5x55mm Mauser chargers and see if they might work.
For French MAS 36 clips, one can substitute the '03 Springfield clip (as this was the prototype for the French design)..and since the Springfield clip was a copy of the M95 Mauser clip ( and M93, M94, M96...) all "wide" clips, one can use Spanish, Latin American,Swedish, even Japanese clips in a MAS36...and to go the whole circle, in 1949, the French issued .30 cal ( "cal 7,62 Balle O") in aluminium clips, identical (except for markings) to the MAS36 rifle clip.
The only one which may have fit problems is the Nato clip ( a bit short) and the M98 clip ( too narrow for the clip guides).