Peel the grapefruit, cutting away and discarding all the exterior pith or pulp.

Strain juice and discard pulp.

Cut the tomatoes in half, squeeze or scoop the seed-bearing pulp into the container and discard the skins, walls and other pulp.

With a small melon baller, scoop out and discard the seeds and pulp.

Separate pulp from skin, and discard pulp.

Halve tomato and discard seeds and pulp.

Discard pulp and seeds.

Discard seeds and pulp, and place cut side down on pans.

Discard pulp from strainer and continue until all purée has been strained.

Press out and discard seeds and soft inner pulp.