My scooter has a blemish: Need your advice!

Hello scooter experts, I have a little problem with my scooter (PGO, T-REX 50). The scooter has already been on the hump for a few years, but is really fast and I am super satisfied with it. Since the last winter he has however a small beauty defect. If I don’t start the scooter about two weeks, I can only get him to run with brake cleaner. Then he jumps immediately and after that everything is fine. Do you have an idea what this could be about And if a repair would be worth it? Background: I drive the scooter just for fun, so it’s more a beauty problem and less dramatic for me. But would still like to know why that is. I’m looking forward to your answers now! Ciao and always a good ride!