I'm kind of hesitant to go check out off-site photos but I took a peek at that one and it's toast, unfortunately.
Pinkish/purplish hues are not a good sign, among others. Does it stink? Or is there a faint 'off' odor near the air filter? (do NOT just open it and take a big sniff, especially since it looks contaminated to me)
I would PC that jar for at least an hour at 15 psi before dumping and cleaning it, or else just toss the whole thing as-is, unopened.
The main thing you want to avoid is opening it when it's still full of live contamination, and if you PC it to clean it out be sure to clean it as soon as it cools off enough to do so and you can expect what you clean out of it to get real funky again real fast, so dispose of it accordingly.
No spawn jar should ever sit around for three months. Even if it was still good I'd be very hesitant to use one that's sat around so long. My spawn is usually colonized and ready for applying to a bulk sub within 5 days of inoculation and I apply it as soon as it's ready. The best results come from keeping the mycelium running, which is why Stamets used it for the title of his last book (it really does like to 'run' and we optimize results by making sure it has "space" to continue running (so just as it finishes colonizing the grain you want to spawn it to bulk to maintain its biological momentum, which does seem to be a real thing in this context).