If a boy has sperm in his hand but he washed it after that if he insert into the girl vagina means there are chances of getting pregnant?

Unlikely: Sperm needs to enter the vagina to get pregnant. If there was no sperm on the hand/finger after washing it thoroughly, and then inserting the finger into the vagina, it would be unlikely to cause a pregnancy (as sperm would need to be in the vagina as stated). But i would not practice this behavior as it is way too risky. Good luck.

Pregnant from hand: It is very hightly unlikely if not impossible to get pregnant under the circumstances you describe.