Newer leaves look better which makes me think this crud was a cultural problem at one time. Or is it insect?

Probably oedema.
Oedema
Oedema (aka edema) is a physiological disorder that can affect all terrestrial plants. It occurs when the plant takes up more water than it can rid itself of via the process of transpiration. The word itself means 'swelling', which is usually the first symptom, and comes in the form of pale blisters or water-filled bumps on foliage. Under a variety of circumstances/cultural conditions, a plant's internal water pressure (turgidity) can become so high that some leaf cells rupture and leak their contents into inter-cellular spaces in leaf tissue, creating wet or weepy areas. Symptoms vary by plant, but as the malady progresses, areas of the leaf turn yellow, brown, brown with reddish overtones or even black, with older damage appearing as corky/ scaly/ ridged patches, or wart/gall-like bumpy growth. Symptoms are seen more frequently in plants that are fleshy, are usually more pronounced on the underside of leaves, and older/lower leaves are more likely to be affected than younger/upper leaves.

Oedema is most common in houseplants during the winter/early spring months, is driven primarily by excessive water retention in the soil, and can be intensified via several additional cultural influences. Cool temperatures, high humidity levels, low light conditions, or partial defoliation can individually or collectively act to intensify the problem, as can anything else that slows transpiration. Nutritional deficiencies of Ca and Mg are also known contributors to the malady.

Some things that can help you prevent oedema:
* Increase light levels and temperature
* Monitor water needs carefully – avoid over-watering. I'd heartily recommend a soil with drainage so sharp (fast) that when you to water to beyond the saturation point you needn't worry about prolonged periods of soil saturation wrecking root health/function. Your soil choice should be a key that unlocks the solutions to many potential problems.
* Avoid misting or getting water on foliage. It slows transpiration and increases turgidity.
* Water as soon as you get up in the AM. When stomata close in preparation for the dark cycle, turgidity builds. If you water early in the day, it gives the plant an opportunity to remove (for its own needs) some of the excess water in the soil.
* Put a fan in the room or otherwise increase air flow/circulation. Avoid over-crowding your plants.

Al

I had the same issues with my kalamchoes and jade, which started when we had so much rain. I didn't toss them and the new growths seem to be healthy.
So if mine had oedema, and I am hoping that the new shoots can continue to grow normal.

Thanks for the diagnosis..I think last summer I had it for a time in a cache pot that got rained in.

..... makes sense as the older leaves are where the symptoms are concentrated. A physiological disorder quite common in the Crassula genus. Best luck!
Al

Despite my best 'ignore and it'll fix itself' it refuses to stop getting spotty and crusty.
Ignoring means, in this clay pot, it spent winter in the basement, now in bright shade to part sun.




So- I am reluctant to give up the fat trunks, I suppose I should or could do some major pruning and rehab of the root situation? Any guesses what this might look like?

Failing that, ( or in the course of doing that) cuttings in fresh pots should grow out of these spots, dontcha think?

Sally, what kind of potting mix are you using? The darkness on the lower half of your pot suggests excessive water retention.

Edema isn't just an overwatering problem, its a general moisture (moisture in soil and humidity) plus lack of air circulation problem.

Don't give up the fat trunks. Figure out how to move the air around the plant and don't water until the leaves start losing turgor.

I agree. Conditions I see in the photo that contribute to overall moisture and limited air circulation are: soil level in the pot is too low, crowded location (other pots and near the wall), previously mentioned water line on the pot which I suspect is too-peaty soil. I'm also questioning storing it in dark all winter; do you have a southern window indoors?

In my experience, an extremely gritty fast-draining media in a shallowish pot (like an azalea pot) virtually eliminates the possibility of overwatering.

This article addresses your symptoms
https://libguides.nybg.org/cra....

Ok, thanks for all this, I will re- read later.
Yep, probably poor soil. Will give thought to another pot, repotting in better soil, and some pruning and another placement.
The only wall of my house with zero windows is the south side.
And no window in any bathroom. Very sad! Next winter if Jade is reviving it will get a better winter spot.

Sally, I relate to the winter storage issues. I have a very small house and while I do have southern windows, space is limited. Two winters ago I finally decided I'd had enough of dragging my bulky jade indoors and I let it die outside in the cold. This summer I have three more succulents to unload to reach my goal of not growing anything that can't stay outdoors in winter (not counting annuals). It limits my choices, and there are some plants I'd dearly love to have, but my desire for simplifying my life and decluttering indoors is greater.

This photo was taken Nov 19, 2021. It was the first time this jade had bloomed and you can see it had survived some frost. It was the moment I decided to say goodbye. RIP. Wish I'd found a good home for her.

Aw, Zoe! Too bad
Well, I forgot I do have two small south windows, they fill up fast. Those cute succulents.

Earlier in this jade's life...
The thread "That is ONE way to see how the roots are doing.." in Houseplants forum

Would this shallower pot be big en ough, do you think?

Some very cautious pruning

Looks fine. I don't think it's significantly smaller than the other to make much difference, especially since you've reduced the top. Just be sure to fill it fuller than the first — the soil line (in the pot on the left) looks good.

I think it looks good too.

I will update when I have time to do it.

Try to make your media much more grittier. For my jades, I prefer pumice, but at times it may be with insoluble crushed granite.
When it is indoors, try to improve indoor air circulation. Run a fan a few times a day. The dynamics indoors will be different, so water well then allow good intervals. It is different outdoors, with my jades here always outdoors, especially this summer, they love frequent watering here since it is extremely hot and dry.

To give you an idea how gritty your media should ideally look like:




Crassula ovata 'Gollum'



I think your Jade is recovering well..it does take time. It will just eventually drop all those crusty, lower, older leaves. For me, as long as the jade still manages to grow a new batch of leaves and there is no soggy part in its trunk or branches, then it is still doing well. Just be patient for now. Fall is coming, so it will be renewed active growing time for it.

I still see good potential for your plant. Continue to keep us posted as it goes.

thanks, tarev!