I also spent about an hour searching the web for these with nary a result. Is all you have are "a few of these" and zero prospects of replacing them with a more modern equivalent? If so, I would cut the leads off flush with the case and then crush the epoxy package in a large bench vice before throwing the parts away, just to avoid the temptation of "designing" this component into a project that cannot be maintained with commercial off-the-shelf parts.
OR... if you are a hobbyist and enjoy resurrecting ancient semiconductors for one-off projects for personal enlightenment and joy... buy or build a transistor tester that will measure the specifications you need to know that are applicable to these two diodes.
FIrst, determine whether you have a plain old silicon device (likely), instead of the more rare germanium rectifier pair or
Schottky rectifier pair, by measuring the forward current as a function of forward voltage. Do this also for a common 1N4004 silicon diode for comparison. If you have a Schottky diode handy, measure that for comparison. Plot the results on graph paper so you can easily compare the characteristic curves. Try to keep the power low, say less than a watt, when performing this forward voltage test to avoid cooking the semiconductor junctions. Perform this measurement quickly, again to avoid overheating the junction, since the epoxy case will allow heat to escape very slowly. Try to keep the duty cycle below five or ten percent. Later, you can measure the case temperature rise above ambient at a particular operating forward current and try to use this information along with the thermal properties of typical epoxies to infer what the junction temperature of the diode is. Try to stay below 100C for longer life.
Second, measure the reverse leakage current as a function of reverse bias voltage applied to each diode. Make sure the measurement is current-limited to, say, 10 microamperes so the diode doesn't self-destruct under avalanche breakdown conduction while making the measurement. If breakdown voltage occurs with less than about 100 volts reverse bias, you may have a zener diode. Zener diodes with established specifications are readily available and inexpensive, so unless you have two that are closely matched, cut the leads off and smash the case of that puppy to avoid future frustration. You should probably do this even if the diodes ARE closely matched since the chances of every obtaining spares are slim to none.
Assuming the diode pair has acceptable forward current capability and acceptable reverse leakage capability, congratulations! You now have an irreplaceable substitute for, say, a pair of 1N4002 rectifier diodes. Build it into a custom circuit and let it be someone else's problem further down the road if it fails. Leave no clues behind that modern substitutions are available! Fully half the "fun" of troubleshooting and repair of ancient electronics is finding "stuff" that will work while satisfying the owner that you repaired his heirloom-quality, veneered mahogany, Wavemaster ALL-BAND Shortwave Radio to better than factory new condition. However, never let them peek behind the curtain. Dangerous high voltages and radiation are present inside!
As
@73's de Edd would say, THAAAS it! With good forward voltage at a reasonable current with sufficient reverse voltage capability, you have salvaged a nice pair of power rectifier diodes. Go play and sin no more.
There are a lot more tests you could do to firmly establish what it is you have on hand, and with that data you could do a parametric search of currently available parts to find suitable replacements, but why bother? Establish the specs for your circuit first, then find the components that meet those specs, then hope you complete your project before the components you have selected become no longer available. Been there, done that, but it's becoming increasingly more difficult to keep up.
