How should I disinfect an old fish tank for a leopard gecko?

[Eeviethegecko]

Hi,
I’m getting a leopard gecko in a few months and I have an old 20(ish) gallon fish tank that I was going to use, I was wondering how to disinfect it to make it safe for the gecko
also, I don’t know if I’m posting in the right spot, sorry if I’m not
Thanks!

 

[panthergecko]

If you are going to get a gecko in a few months. I would use vinegar or bleach and let it air dry for a few weeks.