TL;DR
Most sewing machine problems are lint, not faults. Unplug the machine, lift out the needle plate and bobbin case, brush the packed fiber out of the hook race and feed dogs, and oil only the points the manual specifies with sewing machine oil. Do this every few projects and skipped stitches usually disappear.
Where the lint comes from
Every stitch pulls fiber off the thread and the fabric. That fiber collects in the one place it can: the bobbin area under the needle plate.
Over time it packs into a dense felt around the hook race, the circular track the bobbin hook runs in. Packed lint there causes skipped stitches, thread nests on the underside of the fabric, uneven tension, and a machine that sounds louder than it should.
Fleece, flannel, minky, and batting shed enormously. A quilting session can pack a bobbin area in a single afternoon.
How do you clean a sewing machine?
Unplug the machine, remove the needle, presser foot, and needle plate, and lift the bobbin and bobbin case out. Brush the lint away from the hook race and the feed dogs with a stiff lint brush, wipe the parts with a dry cloth, then oil per the manual and reassemble.
Unplug it first
Sewing machines have a motor, a foot control, and on computerized models a control board.
Unplug it from the wall before removing any cover or reaching into the bobbin area. A machine that starts while your fingers are near the needle is a serious injury.
Do not spray any liquid into a machine, and keep water away from the electronics entirely.
What you need
- The machine's manual, which governs everything
- The lint brush that came with the machine, or a stiff small brush
- A small screwdriver, usually the one supplied
- Sewing machine oil, if your model takes it
- A dry lint-free cloth
- Fresh needles
The step-by-step
1. Unplug it.
2. Remove the needle and presser foot. Discard the needle if it has been in more than a few hours of sewing. Needles are consumables and a dull needle causes half of all stitch problems.
3. Take the needle plate off. Usually one or two screws, or a release on newer machines.
4. Remove the bobbin and the bobbin case. On a front-loading machine the case lifts out. On a drop-in machine there is often a removable ring or race cover, and the manual will show whether yours comes out.
5. Brush the lint out. Work the brush through the hook race, around the feed dogs, and under the needle plate. Brush lint outward and away rather than pushing it deeper.
6. Do not use canned compressed air. It drives lint deeper into the mechanism and can blow moisture from the propellant inside. A brush, or a small vacuum attachment on low, is the right tool.
7. Wipe the bobbin case and the race with a dry lint-free cloth. Check the bobbin case tension spring for thread caught under it, which is a very common cause of tension trouble.
8. Check the thread path. Lint and thread fragments collect in the tension discs and the take-up lever area. Some manuals describe flossing the tension discs with a folded strip of fabric.
9. Oil per the manual. See below.
10. Reassemble, fit a fresh needle, and test on a scrap.
Oiling, which depends entirely on your machine
Some machines need regular oiling. Many modern computerized machines are sealed and should never be oiled by the user.
Read the manual. It says whether to oil, where, and how often. Guessing is how people ruin machines.
Use sewing machine oil only. It is a specific clear, light oil. Do not use general-purpose penetrating spray, cooking oil, or any household oil. Those gum up, attract lint, and can stain fabric permanently.
Use one drop at a time. Excess oil runs onto fabric and ruins projects.
After oiling, run the machine on a scrap for a minute so any excess is absorbed by the scrap rather than your next project.
Why does my sewing machine skip stitches?
The most common causes are a dull or bent needle, the wrong needle for the fabric, lint packed in the hook race, or incorrect threading. Change the needle first, since it is the cheapest and most likely fix, then clean the bobbin area and rethread the machine from scratch with the presser foot up.
How often to do this
Every few projects for a light sewer, and every project for quilting or anything with fleece, flannel, or batting.
Change the needle every eight to ten hours of sewing, and immediately after hitting a pin.
Annual service by a technician for a machine used regularly, which covers timing, internal cleaning, and adjustments a user cannot do.
Cover the machine when it is not in use. Dust falling into the tension discs and the thread path from an uncovered machine is a slow, avoidable problem.
Source: Sewing machine manufacturer maintenance documentation
Sergers and embroidery machines
Sergers produce far more lint than sewing machines, because they trim fabric constantly.
Clean a serger after every project. Brush the knife area, the loopers, and the lint chamber, and empty the waste tray.
Serger knives dull with use and are replaceable, and a dull knife gives a ragged edge rather than a clean cut.
Embroidery machines need the same bobbin-area attention plus regular hoop cleaning, since stabilizer adhesive builds up on hoops and can be wiped off with a little rubbing alcohol on a cloth.
The sewing room around it
Fabric shedding is not confined to the machine.
Vacuum the floor and the surfaces regularly, since fabric lint settles everywhere. A small vacuum kept in the room makes it much more likely to happen.
Keep a bin for scraps and thread ends within reach of the machine. Loose thread on a floor gets into vacuum brush rolls and wraps around them.
Store fabric covered or in bins, both for dust and because sunlight fades it.
Organize tools so cleaning them is easy, the same argument that runs through how to clean artist brushes and palettes and our guide to cleaning tools and equipment around the house.
Other hobby machines in a craft room need their own routine, such as the one in how to clean a 3D printer bed and nozzle.
FAQ
Can you use compressed air to clean a sewing machine?
It is not recommended. Canned air drives lint deeper into the mechanism instead of removing it, and the propellant can deposit moisture inside. Use the lint brush that came with the machine, or a small vacuum attachment on a low setting, and brush lint outward and away from the hook race.
What oil do you use on a sewing machine?
Sewing machine oil, which is a specific clear, light oil sold for this purpose. Never use general-purpose penetrating spray, cooking oil, or household oils, which gum up over time, attract lint, and can stain fabric. Many modern computerized machines are sealed and should not be oiled at all.
How often should you clean a sewing machine?
Every few projects for light sewing, and after every project when working with fleece, flannel, or batting, which shed heavily. Change the needle every eight to ten hours of sewing. A machine used regularly also benefits from an annual service by a technician.
Why is my thread nesting under the fabric?
Usually the top thread is not seated properly in the tension discs, which happens when the machine is threaded with the presser foot down. Rethread completely with the foot up, check the bobbin is inserted in the right direction, and clean lint out of the bobbin area and tension discs.
Do you need to unplug a sewing machine to clean it?
Yes. Unplug it from the wall before removing the needle plate or reaching into the bobbin area. A machine that starts unexpectedly with your fingers near the needle causes serious injury. Never spray liquid into a machine or near the electronics on a computerized model.
Can lint really cause sewing machine problems?
It is the most common cause of them. Lint packed into the hook race and around the feed dogs produces skipped stitches, uneven tension, thread nests, and a noticeably louder machine. Many machines taken in for repair need nothing more than a thorough brushing and a fresh needle.
Craft rooms shed lint and thread into every corner of a house. If keeping up with the rest of the cleaning is the harder job, get a quote or read more about house cleaning services.