Saturday, September 22, 2007

More About Green Cleaning

The internet has lots of pages of green cleaning tips, but some of them are confused and many of them don't work. For example, some writers get mixed up between baking powder and bicarbonate of soda. Other recipes often recommend that you mix vinegar with bicarb to make a sooper-dooper cleaning agent. Actually that would make a lot of impressive looking bubbles but result in something with approximately the cleaning power of salt water. A basic understanding of chemistry (or baking) would help clear some of this up.

The golden rule is alkali neutralises acid, and vice versa.
  • Bicarbonate of soda is a powdered alkali. It's great for cleaning acidic stains. If you mix it with a little water to make a paste, it makes a very gentle scourer. Because the powder is very fine, it won't scratch like salt can.
  • Vinegar is a solution of acid. It's good for cleaning alkali stains, and will dissolve greasy stains. I use it in a plant mister for cleaning surfaces, glass etc.
  • If you add bicarb to vinegar the alkali neutralises the acid. A lot of carbon dioxide gas is released, and when the reaction is over you are left with a neutral liquid. Well, you probably had a bit too much of one or the other, so it will be a little bit acid or a little bit alkali - but there's no way of knowing which unless you measure precisely and understand the chemistry. Either way, the result has very little cleaning power. If a website or a book advises you to mix bicarb and vinegar, then the writer hasn't tested their own tips. I'd disregard everything else they say.
  • Baking powder is a mixture of powdered bicarb and powdered tartaric acid. When dry, nothing happens, but mix them with liquid (e.g. in a cake batter) and they react. Carbon dioxide gas is released - that's what makes your cake rise. The acid neutralises the alkali. Baking powder is no use as a cleaning agent, but it does make great cakes. Again, anyone who recommends you use baking powder as a cleaning agent is confused. Be sceptical about taking their advice.

So that's the lowdown on bicarb and vinegar. They're very useful cleaning agents in their own right, but don't mix them unless you want to make a sink-top volcano for your 5-year-old to play with.

What other options are there for green cleaning?

  • Soap is made by reacting a strong alkali with fat or oil. I make soap at home by reacting lye (sodium hydroxide - drain cleaner) with sunflower oil, coconut oil, olive oil etc. A lot of soap nowadays is made with palm oil, and there are all sorts of environmental problems with palm oil production, but that's a story for another day. The point is that soap is pretty environmentally benign and is a great cleaner. After all, it's what your granny used in the days before Cillit Bang.
  • Hot water is a great asset to cleaning. Use rubber gloves and very hot water, a bit of soap and you can clean most things.
  • Lemon juice is acidic and also a natural bleach, especially in combination with sunlight. But a commenter has pointed out that lemons in Britain have travelled a lot of food miles.

If all the cleaning products you owned were soap, vinegar, bicarb and a pair or rubber gloves, you could still keep your home as clean as you like.

10 comments:

Yellow said...

Thanks Mel, that was very very helpful. I love your 'Dummies Guides' that you come up with. As a comment againt shop-bought products applied with little common sense, do you remember the cleaning lady mum used when she was very ill, that used to spray Mr Sheen onto everything, instead of washing surfaces with soap and water. Mum was changing a computor game on the TV and she found that she could scrape millimeters of wax off the screen because of the build up of spray on polish. She said she had to take a scourer to the telly to remove ot from the screen, and her Laura Croft scores increased exponentially as well.
I only ever use Mr Sheen as an air freshener when relatives are visiting to make them think I've polished before they arrived!!

Nik said...

I'm wondering if there's confusion between bicarb of soda and baking powder since bicarb is also known as baking soda (well is here anyway) and people get mucked up that way?

Unknown said...

Baking powder has other stuff in as well, such as tartaric acid. Don't get them mixed up!

AlecMuffett said...

I often use citric acid powder as a cleaning agent, especially since you can dust it along the lines of scale on the edge of the bath and then spritz it with water to have localised descaling. Moderately strong stuff, though - don't leave it too long on enamel. Descales kettles, helps clean stains...

Oddly you can't buy it in bulk from supermarkets and chemists because apparently it gets used to cut drugs (!) - but homebrew shops have tons of the stuff.

Melanie Rimmer said...

I've never tried that, thanks Alec. I have shedloads of citric acid in the house, partly for winemaking and partly in my soapmaking supplies. It's one of the main ingredients in bath bombs. I buy it from soaping suppliers by the kilo.

Unknown said...

We use bicarb and vinegar to sort the kitchen sink out when it's slow draining. We put the bicarb down the plughole and then wash it down with a boiling water & vinegar combo. As you say, the result is rather volcanic, but it does seem to sort out the problem. It may just be the bubbles - when I was at uni I listened to a lecture on how everyone thinks bubbles are soft and gentle, but when there's a lot of them together they can be really tough.

Melanie Rimmer said...

Muppet, I just use boiling water on its own and find that does the job 9 times out of 10.

Nicole said...

This information is great! I always admired the chemical free cleaning way and now I have a fantastic source to learn from! This is excellent - thank you for posting this!
I'm off to buy some lemons! :D

Anonymous said...

Thanks for posting this. Not being a chemistry major, I didn't understand how these things interacted.

Question: A few days ago I tried to make dish soap by combining Dr. Bronner's unscented castile soap with lemon juice because I love that "lemon fresh scent." But it doesn't work too well, and now I'm wondering if the soap and citric acid neutralize one another? What do you think?

Anonymous said...

Hi Melanie. I tried to reply to the e-mail that you sent me, but my reply bounced back and was rejected. Don't know why. :-(

So here's what I said:

I used Dr. Bronner's liquid soap. Here's a link to info about the soap:

http://www.drbronner.com/drb_sai_liquids.html

I used the "Baby Mild" version. Dr. Bronner's is the soap hippies in the U.S. have used for decades. Check out the story on the web site. There's even a movie about it now.

I added juice from 3 or 4 lemons to about 12 ounces of soap.

Any ideas? I'm not getting much sudsing action and wondering if it's because of the lemon juice.