How do I use the other section of the config to add my own variables properly?

I tried to add this:

$myvar = 20;

But then it doesn't appear the next time config is edited, and gets wiped out when resaving.

v6.2

How about this?

$config['myvar'] = '20';

I have a number of custom variables like this, and this is how I've added them.

That was the problem, thanks.

Happy to help.