They're all pretty much the same, metal cans, soldered shut.
If I have this what is your attached picture. It takes one minute (+ pre work) and it is safely open without any damage so that it can later resolder so it is like it was.
When not have induction equipments...
Simply, small size gas torch (gas soldering pen)
There is screw holes. Fix it to some metal plate with screws so it is some mm distance from plate (pins are then under this plate free free gap)
Fix this plate to place where it is well fixed and so you have enough room for heat every side equally. OCXO can top is now to down. If it is tight it may need some pliers attached with some soft material what do not smelt or burn and do not shrink this can. Typically needed force is light after all solder have smelted between bottom plate and cover.
and sidenote. If there is screw for adjustment, take it off and also plastic/rubber seal out)
Now start heating. Heat these sides near solder joint. Do not so much heat bottom plate for avoid damage in pins joints) Carefully enough fast (not too fast) turn torch around this can over and over until you see solder have smelt (typically after this bottom can drops to floor (note that it is hot so keep something under it. If need pull outer can down with some low force using pliers (pull directly down - if it come some side or corner first it may make it tight. )
Depending torch heating power it need be patient and give enough time for that all solder smelts inside can joint and still keep its electronics without damage. So it need do enough fast for avoid too much time to internal overheat) With some cans it may need even combined cooling and heating but this you have is not this kind of extremely sensitive thing. Just "Brute force" torch and it is open.
It is difficult with what ever kind of irons.
Do not heat bottom plate, heat outer sides, result is better and more safe.
When you close it agen. just do opposite (and if there is adjustment hole take screw and possible rubber seal out) but now it do not need be fixed with screws to any plate. Just free on some suface what is ok for soldering. If you have Metcal or equal it can even solder it but also it can do with torch. Just heat over smelt point and use solder wire. pB solder is better.
When you open it, look carefully if there is inside some tin (or other metal) wiskers. They are not rare inside some these cans.
I have repaired many Rockwell-Collins filters and also of course OCXO's.
Some times not failed but if have need improve some specs.
(example readjust OCXO XTAL temperature regulator so that it setpoint is exactly in XTAL temp/freq turn point for get better temp stability. )
Torch method is fast, bulletproof, easy without expensive tools and also safe (after some knowledge and experience how to avoid pins damage and how to avoid overheat or other damages) .
For get experience there is easy availabe lot of cheap or frree surplus / failed OCXO's for exercise before take some expensive rare OCXO under work.