Ah the local scrach and swivle are bad for the paint. They use acid based chemicals and wash mits coverd in crap !
Re products you need to try few and see what works good for you. There is no specific for the age of the paint. I like autoglym but i also use poorboys and maguires , i have pro kleen snowfoam and for interior i use baby wipes 🙂
Also its woth watching Ammo in youtube to get some ideas. He is a pro !
the milky bars are a pain. You can try some aluminium polish paste but i dont think you can do much about