Polishing Metals (Including Jewellery), Glass, Plastics

Last updated: November 25, 2024

How to polish metals; how to remove scratches from glass (including windscreens and shop counters).

Scratch remover for plastics (including soft plastics such as acrylic and plastic watch crystals)

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REMOVING SCRATCHES FROM GLASS AND PLASTIC
- for glass windows and shop displays
- watch glasses (general)
- watch glasses (professional method)
- watch glasses and acrylic displays (DIY method)
POLISHING JEWELLERY
- professional method
- DIY method
POLISHING SILVER (including removing tarnish)

REMOVING SCRATCHES FROM GLASS AND PLASTIC

- for glass windows and shop displays

This is how scratches were removed in a windscreen factory. A large cotton mop on a polishing motor on its slowest speed, while the mop is spinning apply rouge by holding the block of rouge against it. If the scratch is deep enough to feel with your fingernail it is too deep to remove by polishing. I assume that if this method works on glass car windscreens it will work on ordinary windows, glass shop counters and display cases (even 'watch glasses' providing they are made of glass).

How easy is this to do? Well...it's possible, it's worth a try rather than buying a new shop window or expensive showcase, but it's not necessarily 'easy'. A company specialising in taking scratches out of glass was going to market a D.I.Y. system of mops and polishes but changed their mind. They said, if you are too gentle it simply doesn't work and if you are too enthusiastic the glass gets hot and shatters, which is why they charge a lot of money to come to your shop and polish a scratch out of the glass. So I can't promise it will work but it's certainly worth a try.

- watch glasses (general)

The following refers to watch 'glasses' made of plastic. If it really is made of glass, follow the instructions, above, for glass. If it is made of sapphire (yes, real sapphire, but "synthetic", grown in a laboratory) it will be too hard to polish, you will have to get a new one.

Basically, if the scratches are bad enough to feel with your fingernail, then you won't be able to polish them out unless you are a professional polisher.

- watch glasses (professional method)

I took my own watch 'glass' (it was made of plastic and it was badly scratched) to a jeweller. He took it to his workshop and, ten minutes later, it was almost perfect. He used standard jewellers rouge. As a skilled polisher, he knew just how hard-and-long to polish in order to remove the scratches without totally destroying the 'glass'. So it is possible to polish bad scratches out of plastic but you have to use a polishing motor (you won't manage it by hand) and you do need considerable skill.

- watch glasses and acrylic displays (DIY method)

For the novice, polish plastic with scratch remover. This works well on soft plastics such as acrylics. Typical items made of soft plastics are: some 'watch crystals' (though they should be made of a hard plastic), most plastic display stands, simple handheld magnifying lenses, some very cheap reading spectacles and sunglasses. Scratch remover will not work on hard plastics such as polycarbonate (or any lens described as 'scratch-resistant').

There are many hundreds of different types of plastic, if you don't know if your plastic is 'soft' or 'hard (i.e. whether to use scratch-remover or rouge) try it and see. Start with the scratch remover, see if it works; if not, try the jewellers rouge, see if it works; if not, then the plastic is too hard to polish.

When polishing plastics take great care. My recommendation is: for anything expensive (and all lenses), if you have a choice between throwing it away or trying to remove the scratches, then see if you can remove the scratches, you've nothing to lose; if the item is expensive, you may prefer to suffer the scratches than risk destroying it with over-polishing.

To use scratch remover mix it with water to form a paste the consistency of double cream, apply with a small felt mop on a miniature polishing motor, go carefully - you are only polishing a scratch not drilling for oil. This is the powder used in the aircraft industry for polishing the acrylic canopies of aircraft. As with the rouge, it will only work on fine scratches.

To use jewellers rouge simply hold the block of rouge against the polishing mop as it spins on the motor (or smear it heavily onto your polishing cloth if you are polishing by hand) - there is no need to mix it with anything, it is very soft and will adhere to the mop / cloth.

POLISHING JEWELLERY

- professional method

For the final polish (assuming the item isn't badly scratched) use a soft cotton mop on a polishing motor (e.g. 6 inch mop), as it's spinning press the block of rouge against it until the mop turns red, then press the jewellery against the mop. Any crevices, especially the backs of stones, will become dark red from the rouge. This is normal. Wash out in an ultra sonic cleaner then dry by throwing the item into a big bowl of hot sawdust (e.g. an enamel bowl full of sawdust on a gas or electric heating ring).

For items that are badly scratched, start with coarser polishing mops and coarser-than-rouge polishing compounds.

Learning how to polish everything (e.g. gold brooches, platinum rings, small earrings, large pendants, fancy chains, pitted bronze, brass candlesticks, filigree dishes, silver salvers...) you will need a dozen different grades of polishing compound, several different types of mop, and an awful lot of experience (it takes about three years to train as a polisher).

- DIY method

If the item isn't badly scratched and just needs a final polish, smear rouge (rouge block) onto a gold polishing cloth...and polish. For the inside of a ring use several strands of linen thread, tie one end to an immovable object, smear with rouge, slide the strands inside the ring, pull taught, rub the ring up and down. Any crevices, especially the backs of stones, will become dark red from the rouge. This is normal. Wash the item in hot soapy water, cleaning the backs of the stones with a soft toothbrush then leave to dry on tissue, give it final shine with a clean gold polishing cloth.

Before that final rouge polish you may need to use polishing sticks. These are a simple alternative to a selection of mops on a motor with a selection of polishing compounds.

If you are polishing old and badly worn items, start with a fairly rough grade of polishing stick (this is a matter of judgement!) and work your way through finer grades as the item becomes smoother and shinier. However, if you are starting with a new (or nearly new) item which doesn't really need polishing, but has a stain from testing, then start with the finest grade of polishing stick and if that doesn't work, move on to slightly coarser grades, because you don't want to start by adding scratches!

If you want the item to end up with the brightest 'as new' mirror-finish, you will still have to polish it with jewellers rouge (see above) after using the polishing sticks.

POLISHING SILVER (including removing tarnish)

The method for polishing silver is the same as above. However, if it has gone a dark colour through tarnish (a reaction with the air) remove the tarnish first. Either immerse in silver dip or rub with a special anti-tarnish silver cloth (the red side of the cloth removes tarnish).

If the item is 'as new' (e.g. it is part of your new stock!) and has merely tarnished, then there is no need to go to any effort polishing it, just rub it with the yellow side of the silver cloth (or a gold-polishing cloth if you have one).

Conversely, if the item is scratched and needs polishing, silver dip / a silver cloth will not "polish" it (shine it up), it will merely remove any tarnish.