Remove the skin from tamarinds along with any big strings attached to the fruit. Cut each tamarind into several pieces with your hands.
Rinse quickly on a colander with cold water to remove any dusty spots.
Place in a medium bowl and add 2 cups of hot water. Cover with a lid or a plate and let it rest for 10 minutes.
Mash it with a spatula or your clean hands to squeeze the juice/pulp out of the seeds and the hard fiber.
Add a little more water at the time to strain any remaining pulp. Scrape off any pulp attached to the outside/bottom of the strainer.
In a medium saucepan, add the tamarind pulp from the bowl. Bring to a soft boil and then lower heat to medium-low.
Remove from heat and let it cool down completely. Store in glass jars with an airtight lid in refrigerator.