With high levels of interest continuing in ways to clean that are more natural or use less 'manufactured' cleaning materials here is a method of cleaning silver (or something along similar lines without the access to aluminium foilthat we have today) that would have been in full use 100 years ago, before the advent of multi national chemical manufacturing and supermarkets.
Obviously we would suggest a cautionary approach with the cleaning of any really valuable antiques, just in case the 'au natural' look with age old dirt and patina is more important to the value, and cleaning the item might be detrimental to the antique silver value. But for everyday silver utensils this is an effective method of cleaning.
It’s coming up to the festive time of year again, when everyone is full of joy. Full of joy, at least until the realisation sets in that the silverware hasn’t been out of the draws for a year and tarnishing has crept its way across the top of your forks - joy is then replaced by horror.
Never fear, Clean Cleaner are here to help you out again. There’s nothing we love more than to rescue a friend in need. So, we’ve written this blog post about the maintenance of all things genuinely silver.
The good news is that this one is simple. You will need: a plastic bowl, kitchen foil, bicarbonate of soda, table salt, boiling water, and whatever you’d like cleaned.
Line the plastic container with you kitchen foil and add the boiled water to it (enough water so that all your silver items are below the waterline). Using several sheets of foil should work fine, it doesn’t need to be a continuous covering.
Add a few tablespoons of bicarbonate of soda (2 tbsp per litre), a spattering of table salt, and your silver, this works on the basis of the silver and aluminium being in contact and creating a tiny electric current. Thus, you won’t need more silver in the bowl than can fit evenly without too much overlapping.
The concoction will start fizzing, and that’s a good thing! The bicarbonate of soda is necessary for the transfer of the sulfur ions that form silver sulfide (the tarnishing on your cutlery) to aluminium foil (resulting in aluminium sulfide).
Here is a section from this chemistry website that explains the process in more detail for anyone that liked to think of themselves as pretty nifty in their chemistry class:
Aluminium has a stronger affinity for sulphur than silver, so in this reaction the aluminium simply displaces the silver from the silver sulphide compound, to free the silver metal and form the aluminium sulphide compound:
3 Ag2S(s) + 2 Al(s) → 6 Ag(s) + Al2S3(s)
The reaction itself is actually an electrochemical reaction – essentially, a tiny electric current flows between the silver and the aluminium when they are in contact, and the silver in silver sulphide is reduced (gains electrons) to form silver metal, whilst the aluminium is oxidised (loses electrons) to form Al3+ ions:
3 Ag+ + 3 e– → 3 Ag
Al → Al3+ + 3e
Combining these two half equations gives us the full redox equation for the reaction:
Al + 3 Ag+ → Al3+ + 3 Ag
This explanation is fine, but it doesn’t explain the need for the bicarbonate of soda or the salt during the reaction – and both are vital components. The sodium bicarbonate is required to remove the thin layer of aluminium hydroxide that forms on the aluminium foil; without this, the reaction would be unable to obtain a ready supply of aluminium ions, and as such could not proceed. The reaction between these two also produces hydrogen, which plays no part in the removal of the silver tarnish and is just given off as a gas. The salt, meanwhile, acts as a ‘salt bridge’ – this aids in the transfer of electrons as the reaction progresses, preventing an imbalance in charge and allowing the oxidation and reduction reactions to proceed.
Although the tarnishing makes way for shiny, impressive kitchenware or jewellery, you can’t have it all your own way. One of the secondary chemical reactions is between aluminium sulfide and water releases a small amount of hydrogen sulfide gas which smells exactly like rotting egg (it’s the same gas). Perhaps we should have included a nose peg in the ‘you will need’ section...
Thanks for reading another blog post by Clean Cleaner. We are based in Edinburgh and like to write some great content as an aside to providing exceptional domestic cleaning! Other posts include why bleach is a terrible cleaning product, how to get rid of mould, and the fascinating world of dust.
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Until the next time, friends.