Putting it in the pantry/cabinet should be fine as long you are sure your family won't find it. If you have your own closet then that's an option. You want to make sure your SN is away from air vents, sunlight, any other sources of heat, preventing it from getting moisture inside.
Depending on the size of your bottle or container, you can also put it in a vacuum seal or an air tight glass jar of some kind. Whatever you have to do to make sure it's sealed tight.
Melting point of SN is 271 °C (520 °F; 544 K) (decomposes at 320 °C)
en.m.wikipedia.org
I found these threads about heat concerns:
Hi guys i‘ve ordered SN and it was delivered when i was not at home the status wasn‘t updated and i‘ve expected it to arrive the other day so it was in my mailbox for 8+ hours at 36 degrees im pretty sure i can toss it in the trash now :( should i wait the current heat wave to pass before im...
sanctioned-suicide.net
Does anyone know how quickly sn turns to nitrate after exposure with oxygen? I opened mine a couple of times to do the test but sealed it afterwards. Should I get a new one or is it still good?
sanctioned-suicide.net
Massive FAQ dump . Death . Official "SN Poisoning" Easily detectable, nothing more to it. How does it work exactly? Blood cells do not carry oxygen, though lungs continue to supply it, and brain is still working. Cells in body turn to anaerobic metabolism for a while and eventually...
sanctioned-suicide.net