Mm, mutton tallow. Are there still "real"butcher shops in Merida? Is lamb available there. Cozy up to the butcher for some clean mutton fat, ground and render yourself---on the BBQ in disposable pots (recycle some clean metal cans) to keep smell out of house. From what I have read in the wee hours of this morning, it is simple to do, especially if you get some "clean" fat from the butcher. One site said to chill in muffin pans to make usable cakes of tallow.
Now you have me wanting to make tallow candles. -)