I have always used a two step process.
1. EasyOff oven cleaner takes off shiny chrome, washed with Dawn dish soap
2. Then a few days in brake fluid (dot 3), this variable perhaps five days then
using a wooden sharp toothpick carfully remove the high gloss coating (goop)
I wash then with toothpaste and finally dish soap again.
I know I struggled with this same challenge.
Brake fluid is expensive but it works for me.
The parts are down to the raw plastic