File extraction methods don't work on xbone?
I assuming you're referring to usb or ex-hdd, I don't think it's supported as oppose to ps4 and people are even asking for ms to put that feature for the game clips!
I even questioned if the ss' are even stored in the hdd of x1 because I had the same problem(not gold) and I took over 140+ ss(4.3-2.8MB per ss so around 300-400MBs) yet it doesn't decrease the hdd space and with the pictures getting deleted after a month(my guess is that it's either the xbox one reserved space for them in a temporary space or it is in a temporary server of some sort)
Tho really, if it can be done(which I believe ms is completely capable of, since xbox one is similar to windows and sony already has it...) it defeats the purpose of storing it into one drive or even uploading them into their servers in the first place, so in conclusion its ms wanting you to join gold.