ClassicCar

My farther passed away almost 2 years ago. I helped him care for his cars (currently and every winter put them away and pull them out in the spring. Last summer one was driven, one just moved from one garage to another and the others nothing was done at all. when they were put away batteries are disconnected, gas stablizer added, washed and waxed, covered with car covers and tucked in. One car gas drained and run dry.

now my mother does not want to sell them or drive them. I recently had to move the 66 SS impala convertible which always starts hard after storage. but I found the white interior covered with mold. I got it started parked it outside with top down, wiped all interior and let it dry outside before putting back in the garage. I really need to clean this up. Car runs terrible I think it never got the gas treatment last year so i think bad gas. Hope to register it ,only 1/4 tank so going to fill tank and drive her. All cars are insured but not registered,
Questions and put some miles on her.
cleaning the mold with just interior upholstry cleaner?
preventing the mold leave a window cracked?
anything more i should do for storage longterm