dehumidifier

Hi All, Just scored myself a mint condition 2002 JM Marlin 1894 in 357 which I plan to keep forever. I am purchasing a new safe and stumbled across an article https://www.secureitgunstorage.com/gun-safe-corrosion/ which talks about carpet in safes accelerating corrosion from the formaldehyde...

So, I purchased a bag of silica gel cat litter to use in my safe. Any recommendations what container to use to put it in when putting it in my safe? I want something that I don't have to worry about it spilling if it turns over. Ideas?