Mining and holding. Will not sell in next year or two.
Heading to 6 mil...
Please advice strategy to "cold storage" these coins, since I know that there is no real "cold storage" for burst.
A good method would be to just break the stash up into multiple addresses, each one created with a unique very complex random string, 64-100 characters. Put those passwords on a thumb-drive or two, print them out and put the paper someplace safe, etc, etc...
Your going to hear complaints about copy/pasting but as long as your computer is clean I would rather copy/paste a very strong key, over risking my "type-able" key being cracked, or me miss-typing it. Using common-sense and copy/pasting will be fine.
Maybe someone else has some more detailed info.
Good-Luck
I have mine passwords (+100 char) in .txt files in TC containers. The identical containers are placed on different psychical locations/hardware and not updated, as I have many unused passwords in the .txt files for future use. The container encryption password is, today, something I remember, but would I forget it there is two ways to retrieve it.
It was... rather time consuming to create, and is far from fool-proof - as dear Dev can testify as he had to spend quite some time to "crack" an account with 400K on.

That password was 133 char.