How to fix a stuck zip: snagged fabric, stiff teeth and a slider that will not close

First, work out what kind of stuck it is

There are four common problems, and each has its own fix:

1. The slider will not move because fabric or lining is caught in it.
2. The slider moves stiffly because the teeth are dirty, dry or slightly bent.
3. The zip closes, then splits open behind the slider.
4. A separating zip on a jacket will not start, because the pin is not fully in the box at the bottom.

Problem 1: fabric caught in the slider

This happens most often on coats and on lined dresses.

• Stop pulling. Yanking drives the fabric further in and can tear it.
• Pull the fabric gently away from the slider in the opposite direction to the way it went in, while easing the slider back the way it came.
• Use something thin and blunt, like the end of a teaspoon handle or a flat wooden lolly stick, to push the fabric out from between the teeth.
• Work slowly from both sides. Small movements back and forth usually free it.

Once it is out, check the fabric for small holes or a pulled thread, and trim any loose thread so it does not catch again.

Problem 2: stiff or sticky teeth

Dirt, dried detergent and road grime on boots can all make a zip drag. Brush the teeth first with an old toothbrush to remove grit, then add something to help the slider glide:

• A soft pencil. Rub the lead along both rows of teeth. Graphite is a dry lubricant and is easy to brush off.
• A dry bar of soap. Rub it along the teeth, then work the slider up and down a few times.
• A plain candle. The wax works the same way. Use it unlit.

Use one at a time, and test it on the teeth only, not the fabric around them. Avoid oils and greasy products, which can stain fabric and attract more dirt.

If a single tooth is bent on a metal zip, you can sometimes ease it back into line very gently with small pliers. Be careful: metal teeth snap if forced, and plastic teeth do not bend back well.

Problem 3: the zip splits open behind the slider

If the zip closes but the teeth come apart again straight away, the slider has usually worn and spread open slightly, so it no longer presses the teeth together.

• A gentle squeeze can help. With small pliers, press the two sides of the slider together very slightly, a little on each side, and test it. Go carefully. Too much pressure cracks the slider or jams it.
• If that does not work, the slider needs replacing. A dry cleaner, tailor or cobbler with an alterations service can often change just the slider, which is usually cheaper than replacing the whole zip.

If teeth are missing, the zip itself usually needs replacing.

Problem 4: a separating zip that will not start

On jackets and coats, the pin on one side has to go all the way into the box at the bottom of the other side before the slider can move.

• Make sure the slider is right down at the bottom, sitting on the box.
• Push the pin firmly all the way in, until you feel it stop.
• Hold both sides together at the bottom while you pull the slider up.

If the zip keeps coming apart at the bottom, the box or pin may be worn or damaged, and a repair shop is the best bet.

Looking after zips so they last

• Close zips before washing. Open teeth snag other clothes and can bend.
• Do not force a zip over a full bag or a tight boot. Ease the fabric together with one hand while you zip with the other.
• Keep boot zips clean, especially in winter, when salt and grit get into the teeth. Our guide to buying second-hand winter boots explains what to check on zips before you buy.

Buying or selling a piece with a zip

When you buy second-hand, ask the seller whether the zips run smoothly. On Rewear, tap Message the seller on the listing. A short video or a photo of the zip open and closed tells you a lot. Our guide to buying second-hand safely explains what to do if something arrives not as described.

If you are selling, test every zip before you list and fix what you can. If a zip is faulty, say so in the description. Small repairs like this, and sewing on a missing button, are often worth doing before you list, because buyers notice them.

The short version

Free caught fabric gently from both sides, brush and lubricate stiff teeth with a pencil, soap or candle, and squeeze a worn slider only very carefully. If teeth are missing or the slider has had it, a repair shop can usually fix it.