Mold: m-w.com definition 2: the frame on or around which an object is constructed 3 a: a cavity in which a substance is shaped: as (1): a matrix for casting metal (2): a form in which food is given a decorative shape b: a molded object
A mold can be made of anything with sides and a bottom...and slightly flexible or with movable sides. My first batch of soap was in a silicone pan, the second batch I used a sturdy Batmobile box that housed a very fancy collectible Batmobile (collectible for a seven year old? Nope. Just a very heavy metal car that has tons of cool detail and fun to smash into my new baseboards-ouch!)
Anything really can be used: tupperware, shoe boxes, Pringles cans, lucite (more on this later...), silicone muffin pans, REAL wooden break-away soap molds, stainless steel, plastic...anything, really, except for aluminum.
There are so many interesting choices, but if one wants to make a consistantly uniform soap bar, for selling, than an actual soap mold may be in order...
What do you use?