I've always thought that cleaning/sanitisation is totally under-thought in home-brewing. Am short on time atm (BIABrewer is working me to death) so won't write this post out perfectly but I'm pretty excited about the following...
I just did a brew with Nottingham which must be the biggest bastard of a yeast to clean up after. Last night I even tried scraping at the krausen line with my fingernail and was amazed that the stuff still wouldn't come off. I had resigned myself to filling the whole fermentor with PBW and letting it soak. This is always annoying as the bottom of the fermentor is always easy to clean and filling a fermentor completely with chemical and water just to clean the krausen line also can fill the brewer with guilt

Then I had an idea.
Idea 1: Soak upside down
I have plastic fermentors and I also have some spare lids for these without any holes drilled in them. (You can usually buy these from your home brew store.) So, I made up about 10 L of PBW, instead of 30 plus L, and put it into the fermentor, put the lid on and then turned it upside down to soak overnight. Simple!!!!
This morning I saw zero krausen on the fermentor but gave it a shake anyway. I then emptied the PBW and the fermentor was totally krausen free. If you knew how bad that krausen was you would be as gob-smacked as I was.
Then I got another idea...
Idea 2: Keep some of the cleaning solution "dirt-free".
Instead of having that 10 litres just cleaning filthy krausen, if you have a suitable plastic, sealable container, you could put smaller, much cleaner parts in that container, fill it completely with with cleaning solution (say 5 L) and put that inside the fermenetor. Put the other 5 L in the fermentor as well and then turn upside down to soak.
Next day, you will have 5 L of filthy cleaner to throw down the drain and 5 L of cleaner you can store and use for the next batch. (Cleaner will not deteriorate over time.) On the next brew, just mix that clean 5 L with boiling water and a bit more chemical to bring it up to a nice hot temperature.
How cool is that?
Idea 3: Use plain water as a displacement tool.
Let's say you only had the fermentor to clean and no small parts. What you could do is fill the small 5 L container mentioned above with just plain water. This will save you half the chemical.
The same principle could probably be used in many other ways. For example, if you couldn't turn your pastic fermentor upside down, then maybe drop a whole lot of 2 L soft drink (soda) bottles filled with water in there?
Idea 4: For the Glass carboy folks

Those who have glass carboys could mix up about 5L of cleaner and pour that into your carboy. Now get a party balloon and poke it into the carboy. Now use your garden hose to fill the balloon up. I imagine/hope this would force the cleaner to the brim of the carboy at which stage you can tie the balloon off.
Can you see any other ways these 'upside down' or 'displacement' ideas could work?

PP