You can use WD-40 as a presoak and dish soap as degreaser without hurting anything and it's cheaper than Gunk. Engine degreaser, lighter fluid, kerosene, and diesel fuel are all similar and will achieve basically the same end result although none work to my satisfaction. In fact, no 'off the shelf' automotive cleaner/ degreaser does aside from carb or brake cleaner, and they can take off paint on top of getting expensive.
Personally, I use oven cleaner but there are multiple types with various ingredients so you've got to be careful with anodized finishes or paint that you like- the stuff with sodium hydroxide in it will strip both. I use a different type of oven cleaner on all plastics, rubbers, carpet, and interior parts with no ill effects whatsoever after a small learning curve. It removes decals from switch panels and cigarette lighters so don't use it on those, and it's not safe on "soft" paints. These cleaners are still cheap since I buy them at the Dollar Tree.
Most people don't take the risks that I do, nor do they understand the chemicals that they're using so the recommendations will vary. Some call me crazy and they're not wrong, but being different than the crowd and playing Mad Scientist has its benefits.