How do I send this sort of package?

I have a small bottle of Eve Body Wash, but I emptied everything inside and cleaned it so I could put candy in it to a friend. They're not allowed to have that sort of stuff where they're at, so I'm trying to sneak it. Technically I'm not sending liquid, but can I just send it in the bubble wrap envelope? Do I need to take it to the post office to send, or can I just put it in the mailbox? Stamps?