a bank.
there are many local banks that have safety deposit box service. this is like renting an apartment. your bank give you access to your safety deposit box and you put in whatever you want to put in and then they take it from you and put it in a vault or put it in a safe area.
the great thing about this is that it’s normally safe because when they give you the box, you have the key. you open the box, you put your 1 gram silver bar in there or your 1 gram silver bars, you turn the key, you lock it and then they put it back 