Cleansing & Balancing Chakras

Diana Cooper has done webinars on each chakra, taking you through the chambers of each one to clear and cleanse them.
She also wrote about it in at least one of her books, clearly mentioning the theme of each chamber of all the chakras.
You can buy the recordings of these webinars for 11 Pounds. You can also go for the one(s you feel you need most. The one(s) you have most trouble with. You could use the recording(s) over and over, 1 or 2x a week for instance, to get the chakra sorted.

In my experience though, certainly the first 3 take a lot of work. It's not a miracle thing to cleanse and clear a few times and Bob's your uncle.
Chakra & aura cleansing & balancing comes with a helluva lot of personal growth & development.
All your issues and traumas are to be found in your first 3 chakras. With that there are also things that have affected the Heart & Throat chakra.
That includes things from past lives.

So there is no miracle 'cure' other than to work through most of your issues.
Everything you do clears the chakras further.
Since there are layers it may take years, but everything you do get you closer.

The good news:
I do think what Abraham Hicks says goes here too: getting to approx. 80% is enough to be able to get 'higher'.
In other words, you don't have to clear out everything in order to grow.
In actual fact, looking back, I began to grow and evolve way before I even got to 80% cleansing.
As I said, each thing you work through, gets you further.

More good news:
Oftentimes when you clear & balance things on one chakra it also sorts out another/others.
For me this is mostly working on the Sacral and/or Navel. It then also does a lot of balancing on the Solar Plexus, Throat, and so on.
So most of my work is on the Sacral and/or Navel.

A direct method to use that is very helpful (you still may need to work through issues though!):

Go over a chakra with your hand and move counter-clockwise for at least 3 minutes.
You do this a few centimeters above the skin, but experiment, sometimes you need to start further away. Sometimes it's wider circles, sometimes smaller, just feel. Follow your intuition, also for the speed. For me moving slow feels really good.

After at least 3 minutes you change to move clockwise. Also at least 3 minutes.
This smoothes the energy of the chakra again so you cannot skip this. Very important step!!