At first we must made a clear cut between curable and uncurable mates. Among the curables we find the wooden and pumpkin based ones.

Let's begin with the curables: We should fill the mate to a third of its volume with yerba and fill it with boiling water. After we leave it for half an hour, we will notice that a third of the water has been absorved, so it should be replaced again with boiling water; leaving it this way until next day, when it should be emptied. Then, with a little spoon, we must scratch the inner walls to clean any remaining "hollejo" (the bitter remains of the yerba); and after cleaning the mate with boiling water again, it is ready for use.

For the wooden ones, it is recommended to apply a layer of cooking oil or butter in order to achieve a better result. Only in the event of the wood being from a "Palo Santo" tree, the wet yerba should be left from the last use, or it should be filled with water to prevent the wood for drying and cracking. The mates of horn or bone should be left with detergent for 24 hours before curing them with yerba to eliminate a grease layer that produces a bad aftertaste. In both cases, later the curing process continues exactly the same as in the case of the pumpkin based mates.

And something about the incurables too:
All of the other mates types (aluminium, or other metal, plastic, glass, pottery or others) are incurable. With a simple wash they are ready to be used.