One of the things that kills wet electronics is the dried residue that is left behind, creating shorts. Alcohol will wash away the water and leave no residue after it dries.

If the device has ink or glue you'd like to try to preserve, deionized water will mostly work too.

The easiest option is to just fill a plastic food bag with solvent, throw your part in, seal it with a clip and float it in your ultrasonic bath. The bag contains the vapour for safety, and it's easy to switch between different solvents and solutions.

And someone is already doing it:

https://besservacuum.com/en/ultrasonic-food-treatment-machin...

It did get significantly hot after a while. And smelly, so it was surely aerosoling (is that a word?) somewhat.

I did it outdoors and away from anything that could catch fire because it felt rightly sketchy.

Also kinda explody.

I ruined a Thinkpad display the same way in the past, so I went for broke.

Where I am ethanol (EtOH-95%, H2O-5%) is much cheaper and much more readily available and works almost as well. If silica gel is not available, then a fan works well followed by a warm (not hot) oven baking. Make sure the alcohol has essentially all evaporated first.

Keep in mind that some components can be affected by both EtOH and propan-2-ol — component markings, coil doping resins can dissolve, etc. Both alcohols are also good at removing solder flux resins/residues. (Oh for the days when freon and freon mixtures were available, component damage never happened.)

Devices with power transformers pose special problems, best to dry with alcohol first (hoping enamel coatings on wire aren't softened), then bake in oven on warm heat for a long while, sometimes 24 hours or more is necessary. With transformers it's important that this is done as soon as possible after wetting.

Edit: as I'm reminded by nyanpasu64 keep both alcohols away from LCD screens (likely all screens). I had a netbook PC and put it in a carry bag with a bottle of EtOH and it leaked. The PC still worked but the screen suffered the same outcome.

Here, one liter bottles of denatured ethanol are available in every supermarket everywhere, and up to 20 liters available in hardware stores (at bulk rates it's even cheaper).

For comparison, here denatured ethanol costs about $5/l [in US dollars] versus isopropyl at between $25 and $30/l.

Some people will drink EtOH whether it's denatured with MeOH, etc. or with the much safer denatonium. Why blind or kill these people when one doesn't need to? Sure, EtOH will likely get them anyway but why should the State be their executioner?

There's something awfully wrong with that I reckon.

Amazon wouldn't even ship the stuff here. I'm coming to realize that any truly potent or powerful substance is strictly off-limits in consumer spaces. Plenty of good reasons for that. But such things as pure isopropyl and pure H2O2 are so versatile and tantalizing to have on-hand, rather than household cleaners with proprietary formulas, as much dilution as possible, unique MSDS, and obnoxious fake fragrance.

I can walk down an entire aisle in the hardware store, chockablock with bottles of household cleaners, and they all amount to 2 or 3 active ingredients, endlessly remixed for credulous homemakers.

"I'm coming to realize that any truly potent or powerful substance is strictly off-limits in consumer spaces."

There's no doubt about this and it's a damn pain. Outside industrial settings, chemicals that really work are becoming very difficult to get. I accept that highly concentrated (say >50%) H2O2 is dangerous and not something I want or need, and fuel grade (>70%) needs special handling thus the need for controls, but concentrations of about 20% are useful for bleaching where sodium hypochlorite is unsuitable, etc. For example, 6% H2O2 often isn't strong enough to remove foxing from documents, books, etc. so having ready access to a more concentrated solution that I could dilute to suit would be very useful.

It wasn't always like this, I'm old enough to remember when I could get most chemicals I wanted with little effort. Unfortunately, both occupational health and safety and terrorism have put the kibosh on ready availability, controls and restrictions have screwed all of us legitimate users.

Of course, restrictions covering to whom chemicals are sold haven't detrimentally affected the chemical companies one iota, in fact I'd maintain they've benefited them. They've proteced companies from potential lawsuits when users misuse chemicals and they've provided endless possibilities for them to market nigh-on-useless products to naïve consumers like the household cleaners to which you have referred. I could give examples of how some common household products have become less potent over the years but it'd take a full blog to go into details.

There's another downside here too, the less consumers know about the chemicals they use the more unskilled they become at actual chemistry—even if taught chemistry, using products whose ingredients are unknown doesn't add to their understanding. That's also a matter that I've not time to elaborate about here except to say lack of knowledge about chemicals is one of the significant reasons why society is becoming overly chemical-phobic.

https://www.youtube.com/watch?v=6tHInlFfMcM

(By default, I've been assuming it's not sufficiently safe.)

So by itself cobalt chloride could not cause any problem.

However, I have no idea whether the cobalt chloride is not mixed with some organic binder, to make it stick to the silica gel beads, which could burn in the oven, though that is also unlikely to happen before all water is removed from the gel, allowing an increase in temperature above the boiling temperature of water.

By using low microwave power and short time, so that no boiling of the contained water should be seen, it should be possible to dry even beads with cobalt chloride.

Also, where are people even still getting cobalt chloride gel? Do they still make it? I sure wouldn't buy any.

I wouldn't even buy the orange to green stuff by choice these days for anything DIY, it's still too toxic when mechanical hygrometers are cheap.

All ionic cobalt salts are toxic so cobalt chloride is not used as an indicator in silica gell packaged for use with food. That said, it's an excellent indicator for telling whether your silica gell is still working or not.

These fit the bill. Assuming they're not straight-up lying or anything...

https://www.amazon.com/Rechargeable-Desiccant-Dehumidifiers-...?

You can check the color to see whether it's time to microwave them, and whether they are dry once you microwaved them.

It is certainly not something like a poison, where small quantities can have harmful effects, at least not for most people.

Like nickel, cobalt can cause allergies in some people, in which case repeated exposure can have serious effects even in small quantities, in those humans who are sensitive to it.

The instructions on tge cover say 3 minutes at 700W in the microwave.

TIL about the microwaving trick. I'll have to find out more about it. My concern would be the gel beads popping from internal pressure.

I did find a clever solution online that tried to induce mechanical suction on your phone to force the vapour out, but it was too expensive for a one off use.

In the end I had to resort to the food dryer anyway, after the silica gel failed to work.

I use silca gel for storing 3D printing filament and long-term clothes storage.

The color indicating ones are useful so you can see when they are dry.