Sterilize bottles. I use my dishwasher sanitize setting and high heat dry just before bottling. Alternatively. Fill bottles with water, transfer into a large pot and add more water to cover. Bring to a boil and boil for 10 minutes. Let cool and dry top rack. If you choose to dry in the over, you'll have to remove caps for obvious reasons

Using a large blender or food processor, blend pineapple and watermelon chunks. Blend in small batches and strain using Elliesbest nutmilk bag or a cheesecloth.

Transfer juice into a clean pot. Heat up to 70 degrees, stirring and keep at this temperature for about 1-2 minutes.

Carefully transfer into heated bottles. Refrigerate and enjoy when cold.