Milagritos (or milagros) are small amulets that have traditionally been placed on sacred objects, pinned to the clothes of statues of saints or hung with ribbons on altars or shrines.
In general, the believers would ask their saint for a favour and once they had obtained it, they would make a pilgrimage to the shrine where the statue was located. Finally, they would place the milagrito as a sign of gratitude and devotion.
Each milagrito can have different meanings and uses depending on the interpretation of the user. For example, eyes can be used as part of a vow to improve the condition of the eyesight (cataracts, myopia etc.) but also in a more allegorical way to represent observation. On the other hand, a heart can simply represent the organ itself or it can represent love in general.
The milagritos are not a craft exclusive to Mexico, but are also found in other American countries such as Peru and even in Italy and Spain where they are known as exvotos and are usually made of wax.