TL;DR
Unplug a treadmill before you clean any part of it, because the belt can be driven by the motor and a powered machine is not something to reach inside. Vacuum under the motor cover and around the frame where dust collects, wipe the belt and deck with a barely damp cloth, and lubricate the deck only with the product and interval the manual specifies.
Unplug it first, every time
A treadmill has a motor, a drive belt, rollers, and a control board carrying line voltage.
Unplug the power cord from the wall before removing any cover, reaching under the belt, or vacuuming inside the machine. Remove the safety key too.
Do not spray any liquid onto the console, the motor cover vents, or the frame near the electronics. Liquid gets into places you cannot see and shorts things you cannot reach.
If a treadmill has an electrical fault, is tripping a breaker, or smells hot, that is a service call rather than a cleaning job.
Source: Consumer Product Safety Commission home fitness equipment safety guidance
How do you clean a treadmill belt?
Unplug the machine and remove the safety key. Wipe the top of the belt with a cloth barely dampened in water with a drop of mild soap, working from the middle outward, then wipe with a clean damp cloth and dry. Vacuum the frame, the deck edges, and under the motor cover.
Why dust is the real problem
The single biggest killer of home treadmills is dust in the motor compartment.
Carpet fibers, pet hair, and household dust get pulled in by the motor's cooling fan and build up on the motor, the control board, and the fan itself. The board runs hotter, the motor runs hotter, and eventually something fails.
The belt sheds its own dust as it wears, and that goes in the same place.
Vacuuming the motor compartment once or twice a year does more to extend a treadmill's life than anything else on this list.
The step-by-step
1. Unplug it and remove the safety key.
2. Vacuum the exterior and around the base. A brush attachment on the frame, the side rails, and the floor around and under the machine.
3. Wipe the belt. A cloth barely dampened with water and a drop of mild soap, over the running surface. Move the belt by hand to reach the whole loop. Do not soak it, and do not use solvents or oil-based cleaners, which can make the belt slip.
4. Wipe the side rails and the frame. These take sweat and shoe scuff.
5. Clean the console carefully. A barely damp cloth, wiped on the cloth rather than sprayed on the panel. No ammonia and no alcohol on a coated display, both of which damage anti-glare coatings and printing.
6. Reach under the belt edges. A vacuum crevice tool along the gap between the belt and the deck removes grit that would otherwise abrade both.
7. Remove the motor cover and vacuum inside. Usually a few screws at the front. Vacuum gently, keeping the nozzle from banging the board or the wiring. Do this once or twice a year, or more with pets in the house.
8. Refit the cover, plug in, and test.
Lubrication, and why it is not a cleaning step
Most treadmills need silicone lubricant between the belt and the deck. That reduces friction, which protects the motor and the belt.
Follow the manual. It specifies which lubricant, how much, and how often. Intervals vary widely by model and use, and some belts are pre-lubricated and must never have anything added.
Use only the manufacturer's specified product, normally a 100 percent silicone treadmill lubricant. Never use general-purpose penetrating spray, cooking oil, furniture polish, or a silicone product containing petroleum distillates. Those attack the belt backing and the deck surface.
Do not over-lubricate. Excess seeps out the sides and makes the belt slip, which is its own hazard.
A belt that squeals, hesitates, or feels like it drags under a footfall usually needs lubrication or a tension adjustment. Both are in the manual.
Why does my treadmill smell like burning?
A hot or burning smell most often means a dust-clogged motor compartment, a dry deck creating excessive friction, or an overtightened belt. Unplug the machine, vacuum inside the motor cover, and check the lubrication interval in the manual. A persistent burning smell after that needs a technician, not more cleaning.
Stop using a treadmill that smells hot until the cause is found.
Dealing with the dust downstairs
A treadmill on carpet pulls carpet fiber into the motor with every session.
A dense equipment mat under the machine reduces that considerably, protects the floor, and cuts vibration transmitted through the house. It also gives you a defined area to vacuum.
Vacuum the mat and around the machine weekly. Move the treadmill and clean underneath every few months, since that is where the heaviest dust accumulates.
Keep the room ventilated. Sweat that dries fast is easier on every surface in the room, the same principle as in how to clean dumbbells and vinyl bench padding.
Ellipticals, bikes, and rowers
The same logic applies with less complexity.
Wipe handles, seats, and consoles after each session with a barely damp cloth and mild soap, then dry.
Vacuum around the flywheel and the base, since dust builds there the same way.
On a rower with a slide rail, wipe the rail clean with a dry cloth. Grit on a rail makes the seat rough and wears the rollers.
Follow the manufacturer for any chain or flywheel lubrication. Most modern indoor bikes and rowers require almost none.
A realistic schedule
After every workout: wipe the console, the handles, and the rails, then dry them.
Weekly: vacuum around and under the machine, and wipe the belt or the frame.
Monthly: check the belt tension and alignment, and clean under the belt edges.
Every six to twelve months: unplug, remove the motor cover, and vacuum inside. Check the lubrication interval in the manual.
Keep the manual somewhere you can find it. Everything model-specific lives in it, and none of it can be guessed at safely, which is the same rule that governs most powered gear in our guide to cleaning tools and equipment around the house.
The softer gear in the same room has its own rules, covered in how to clean a yoga mat without degrading it.
FAQ
Do you need to unplug a treadmill before cleaning it?
Yes, every time. Unplug the power cord from the wall and remove the safety key before wiping the belt, reaching under it, or removing the motor cover. The motor can drive the belt, and the machine carries line voltage to a control board inside. Never spray liquid near the console or vents.
How often should you vacuum inside a treadmill?
Once or twice a year for most homes, and more often with pets or in a carpeted room. Dust pulled into the motor compartment by the cooling fan builds up on the motor and control board and makes both run hot. This single task extends a treadmill's life more than anything else.
What lubricant do you use on a treadmill belt?
Only the product the manual specifies, which for most machines is a 100 percent silicone treadmill lubricant. Never use general-purpose penetrating spray, cooking oil, or any silicone product containing petroleum distillates, and never lubricate a belt the manufacturer says is pre-lubricated for life.
Can you use disinfecting wipes on a treadmill console?
Use a cloth barely dampened with mild soapy water instead, wiping the cloth rather than spraying the panel. Ammonia and alcohol damage the anti-glare coatings and printed markings on many consoles, and liquid running into the button seams can reach the electronics underneath.
Why is my treadmill belt slipping?
Usually belt tension that has loosened with use, or too much lubricant making the belt slide on the deck. Both are adjustments covered in the manual. A belt that slips under load is a fall hazard, so stop using the machine until it is corrected, and call a technician if the manual's steps do not fix it.
Should you put a mat under a treadmill?
Yes, especially on carpet. A dense equipment mat cuts the amount of carpet fiber pulled into the motor, protects the floor underneath, and reduces vibration carried through the house. It also gives you a defined area to vacuum weekly, which keeps the dust load down.
Home gym equipment collects the dust from the whole room, and the room shows it. If keeping up with the rest of the house is the harder job, get a quote or read more about house cleaning services.