I got a piece of Maylassian wood that has been on the top counter in the garage for the past year. It has dust from all that time. Can I safely add this back to the aquarium? Will rinsing it be enough or?

Also as an added question, do pacman frogs like warm water to soak in? I've never heated the water in the water dish and my pacman only uses it maybe once a month or so. I don't know if it's because he's shy or he just doesn't like room temperature water. His aquarium is currently about 80-85 degree with a back of the tank heater. The water dish is currently on the hottest side.

He only uses the water dish at night and when the day comes he gets out.