Fix your smoke, snow machine, steam mop solenoid pump.

Every year at Halloween and Xmas people dig out their smoke, snow and foam machines and discover that while they are heating up or blowing just fine, there's no smoke, snow or foam coming out. The usual culprit is the pump, a very common solenoid pump used for its cheapness and predictable throughput.
In smoke machines the heater block can also fur up and block any passage of liquid, but it's easy enough to narrow down the fault by disconnecting the pump and seeing if it is actually pushing liquid through. (A blocked heater usually requires replacement of the heater block or whole machine.)
This video shows how to identify, open and clean the classic pump.
Always unplug the unit completely from the mains supply when working on it. Don't trust the machines switch to make it safe to work on. These machines are usually cheaply made, have lots of grounded metal and involve working with wet hands. All a recipe for a zinger of a shock of enough magnitude to ruin Christmas.

If you open the pump and it immediately goes BOING! and all the springs and things shoot out and scatter round your workshop then you can still buy a complete new pump on eBay for a low price. Make sure you get the same style for pipe connections and the correct voltage rating.

These pumps have a rough life, especially in snow machines where they are pumping a mixture of water and detergent, which is tough for most other pumps to handle too. It's made worse by long periods of storage when rubber seals perish, gunk forms and corrosion occurs.

While maintaining your snow and foam machines it's worth cleaning them out too in case goo has grown in the tanks. This is less of a problem with smoke machines due to the sterile nature of the fluid and inherent pasteurising as it passes through the machine.

It does help to flush smoke machines through with some white vinegar in distilled water. Do it outdoors and then flush it through with some fresh smoke fluid afterwards.

The solenoid pumps are also useful for other things too.

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