The watermelon experts will tell you that the first couple of fruits of the watermelon plant should be removed because it is better to retain the third or fourth fruits. The experts don't tell how to remove the first fruits. The assumption of most is that they could be clipped with the use of scissors.
In Oton , Iloilo, the growers have a practical way of eliminating the first fruits. They water the plants with a solution of urea fertilizer. Because urea is nitrogenous and it is for vegetative growth, applying the same on newly fruiting plants will abort the small fruits.
That's more practical than using scissors to remove the small first fruits. You are fertilizing the plants and removing the fruits that are not desired to develop. It could mean additional labor cost to remove by hand the fruits, especially when one is growing thousands of plants.