You probably will not like my response as I'm old school and believe in the old saying, "Better living through chemistry." I grow a good number of Echies in SE Michigan. Every fall I get the same thing on a number of them. I have instituted a fall routine of spraying all of them with two different fungicides about a week apart. It's the only method I have found that works for me. And yes, the affected leaves are nasty looking! Both fungicides are available in either of the BBS as a ready to use or concentrate.

Immunox

Daconil

Thank you, I'll look into those.

I'll second the Daconil.

Another thing you might try if you'd rather not have Daconil in the house--and I can understand that although it really is pretty harmless even indoors (seriously, you can use it the day of harvest on many things)--is the following.

Now a warning. Comparatively speaking, it's a harsh antifungal, it'll clear the deck of any fungus by shifting the pH on the leaf by quite a lot temporarily and dessicating the poor things. For PM, that's exactly what we want. This is harmless to you, your pets, insects, etc., however, and you almost certainly have it in your home and use it when baking. If you bake. I do not bake.

Baking soda. The equivalent of 1 Tbsp in 1 gallon of water, plus 1 tsp of soap (also a fatty acid salt, dessicant when dry, and pH-shift toward alkaline). Spray on the plant, including the soil and pot where the PM is hanging out and has spores. Let dry for several hours, Rinse off with a gentle water spray at room temperature (you don't really need to rinse the soil).

The recipe doubles and halves easily, and keeps, so if you make a quart, 1/2 tsp of baking soda plus about 1/4 tsp of soap (this is not an exact science).

Oh--and yes, I've used this on the most tender plants, including seedlings a few days old. I've also used Daconil on seedlings. Both are very safe and very gentle, but your succulent is also very, very delicate. Even PM can damage it whereas a zinnia merely laughs at PM.

I haven't use Immunox, but have heard good things about it, and trust that BikerDoc knows what (s)he is talking about.

Be very careful, keep an eye on the plant, and test these first before using them wide-scale on your individual plants.