The Power Of Dilution
Dilution is a quick way to get something quite clean, if you're not worried about absolute cleanliness.
It's easily shown with a little bit of data.
For the example in case, I was using an old washcloth rag as I touched up the outside of my house with caulk. It's a water-based caulk which readily rinses off.
I used an old pitcher with some 5" of water in it, as a wash basin. Whenever the rag got fairly gunky, I'd drop it in the pitcher and knead out the caulk. This also rinsed my hands.
At first I only did one rinse: Fill the pitcher with fresh water, drop the rag in it, knead out the caulk, and dump out the water and do more caulking. But I found that my hands were getting a little sticky after a few hours of work; there was still a bit of caulk left after that rinse.
Then I started rinsing twice and my hands felt much cleaner.
How much difference did that extra rinse make?
A Demonstration of Dilution
I used an old pitcher and rag. I weighed them when completely dry, then with a typical 5" or so of water (for caulk rinsing), then I dumped the water and wrung out the rag and weighed them again (water residual). This was a quick dump of water (one second fling) and a two-second squeeze of the rag... I'm not trying to test how dry I could get them. Quite the opposite: How much dilution do you get when you are keeping moving fast while doing a job? I'm testing the worst case dilution scenario; in other words, it would only be better if you wrung your stuff better.
Data
- Pitcher and rag, completely dry: 195.0 grams
- Pitcher and rag with about 4" of water: 891 grams
- Pitcher and rag after dumping water and squeezing rag a couple of seconds: 235.2 grams
Calculations
- Net total of water (full - dry): 696 grams (24.5 ounces)
- Net water residual (wrung - dry): 40.2 grams
- Percent water left: 5.78%
- Inverse (1/.0578): 1 in 17.3
Extrapolation
Let's say 5% of the original water is left, to make calculations easy. This is just a power calculation (0.05n); calc different percents yourself, if you want.
| Rinse | Percent Left | 1 in |
|---|---|---|
| 1 | 5.000000% | 20 |
| 2 | 0.250000% | 400 |
| 3 | 0.012500% | 8,000 |
| 4 | 0.000625% | 160,000 |
| 5 | 0.000031% | 3,200,000 |
Demonstrated
It's easy to see why the second rinse made a big difference. A third rinse would probably not make an appreciable improvement in my situation if you already only have 1 in 400 parts (a quarter of one percent) of the original liquid left, as of the second rinse. But for your purposes, you may want more.
Dilution is a simple and reliable strategy for removing impurities quickly.