Calabashes (kwi) are commonly used for food offerings and may be painted with the image or sacred sign (veve) of the lwa concerned.
Sequin-decorated bottles are placed on altars to honor the lwa.
Libation bottles, decorated and undecorated, are placed on Vodou altars and brought out for ceremonial libations.
Clear bottles with plastic doll torsos are arresting but rarely found on altars. They are used in divination, and also as charms to keep away evil.
Cloth dolls are used chiefly as mediums: they carry messages to the spirit world. Left at the graveyard or the crossroads, they may have notes in secret language pinned or tied to their bodies. China, rubber, and plastic dolls are sometimes also used to represent the lwa. Dolls stuck with pins used for harm are a Hollywood fantasy and a staple of tourist shops.
http://www.amnh.org/exhibitions/vodou/tools2.html