Wash tomatoes and squeeze out the juice, blend it till smooth and cook in a pot until it becomes very thick.

Put the already washed glass container with the lid in a pot which is completely immersed in water and allow it to boil.

Bring out the sterilized bottle and put in the cooked tomato paste while it is still hot and cover it. Put the bottle back into the pot until it boils. Allow it to cool down completely and bring it out from the pot and keep it safe for future use.