Tools rarely die from being dirty. They die from how people clean them. The three usual culprits are water where it should not be, solvent on plastic, and compressed air pointed into a vent.
Before anything: disconnect
Battery out. Cord unplugged. Every time, including the thirty second cleanup you were only going to do quickly.
This is not only about accidental starts. A tool with power connected can also carry current into a place you are about to introduce moisture or a metal brush.
The basic method
For nearly every power tool, the sequence is the same:
- Brush loose debris away from vents with a stiff nylon brush
- Vacuum the vents and the seams rather than blowing them
- Wipe the housing with a cloth that is barely damp, then dry it
- Clean contacts and chucks dry
- Let everything sit until it is definitely dry before it goes in a case
Note the vacuum. Suction pulls debris out. Air pushes it in, past the fan and into bearings and windings, which is exactly where you did not want it. That single change extends the life of tools used in drywall dust and concrete dust more than anything else on the list.
If you do reach for air, keep the pressure low, aim across openings rather than into them, and wear eye protection, because the failure mode is dust returning at speed.
Solvents
Brake cleaner, acetone, lacquer thinner, and similar solvents do a wonderful job of cleaning grease and a very effective job of destroying the tool.
Most tool housings are glass-filled nylon or similar plastic. Aggressive solvents cause crazing, brittleness, and eventual cracking, sometimes weeks later. They also attack rubber overmold, dry out seals, and strip lubricant out of bearings if they wick inside.
Keep solvents for metal parts that are off the tool. For housings, mild soap on a barely damp cloth handles almost everything, including the black hand grime that builds up on grips.
Batteries and contacts
Battery packs get a dry brush and nothing else. No water, no solvent, no soaking a rag.
The terminals collect metal dust in a truck bed, which is worth checking, because conductive debris across contacts is the kind of problem that becomes a heat problem. A clean dry brush or a wooden pick handles it.
Retire any pack that is swollen, cracked, has been submerged, or is showing corrosion at the terminals. That is not a cleaning job.
Blades and bits
These are the one place a real cleaning product belongs.
Circular saw and miter blades load with pitch and resin, which increases friction, raises heat, and makes the blade cut worse long before the carbide is dull. With the tool disconnected, remove the blade, use a product intended for pitch removal, and scrub with a brass brush that will not scratch the plate. Skip harsh caustic oven cleaners, which can attack the braze holding carbide teeth.
Dry the blade fully and apply a light protective coat if it is going into storage, because bare steel in a humid garage rusts fast.
Drill bits and driver bits mostly need the buildup taken off and the shanks kept clean so they seat properly in a chuck.
Chucks and moving parts
A keyless chuck fills with fine dust and starts slipping. Open it fully, brush out the jaws, and blow across it lightly if needed. A very small amount of dry lubricant is acceptable on some chucks; heavy oil is not, because it collects dust into paste.
The same principle applies to saw guards and adjustment levers. Clean and dry beats greased and gritty every time.
Storage
Dry, cased, indoors, with packs off the tool. A cleaned tool that goes back into a wet truck bed did not get much benefit from being cleaned.
Ten minutes at the end of the week, done this way, is the difference between tools that last a decade and tools that quietly get worse until you assume they were cheap.