Emotionally let go of grudges, yes. Logically let go of grudges, it depends.

Do not let the grudge rule your life. It isn't with wasting your emotional energy on something trivial.

But grudges can be logical. Depending on the grudge, it could be good for you to hold onto it. If someone is toxic, it might be best to just stay away from them. Perhaps it makes sense not to lend a person money who has a habit of making poor choices with that money.

A grudge by the nature of the word implies emotion. But often the reason for the emotion has bearings in logic and safety. It was the emotion that finally allowed you to make the right choice. Letting go of the emotion doesn't mean you should go back on the choice.