I have done both. When I left the white paper on the inside of the foil I found that the white and foil liners sometimes separate after baking and don't look as nice for presentation. (It might have just been the brand I used.) I have taken the white ones out and used the foil baking cups by themselves and they work great. Just keep in mind cakes bake more quickly in foil liners. I then use the white ones for baking other things.
You don't really 'use' a baking dish. You can put food on it, tin foil, aluminum foil, non-stick spray, etc.
only when baking
The "inside" of tin foil is the dull side. The "outside" of tin foil is the shiny side.
You lay the foil over the baking sheet. You do this to protect your sheet and to make whatever you are baking easier to remove. If you have a non-stick coated sheet it may not be needed.
If you mean to line the muffin pan with foil, then no. The muffins will stick to the foil and you'll have trouble getting it off without tearing the muffins. You can simple butter and flour the pan and not use any lining.
The baking soda and vinegar will react making a salt called sodium acetate and the gas carbon dioxide (which will form bubbles) and water. The tin foil will not react with anything and will remain tin foil.
Ingredients1 1/2 c Peanut butter; smooth orcrunchy 5 oz Semisweet chocolate; 5 sqchopped 2 tb Butter1 pk Marshamallows; miniatureLine 2 muffins pans with 24 foil baking cups. Melt peanut butter, chocolate and butter over low heat or in microwave at Medium for 2 minutes. Stir until smooth. Fold in marshmallows. Spoon into baking cups; chill. MAKES ABOUT 24 CUPS
white
Liner refers to something between the food and the dish or pan. This can be a crust, tin foil, wax paper, etc. lining the dish or pan before the food is put in.
No, you never ever do. It is dangerous.
For most things no its not worth it, just use a bit of trial and error. Most things don't need specific greasing, but occasionally you get something that has the adhesive properties of superglue, then grease the tin next time. (all the crispy bits will slide off after a good soak)
Wrapping food in foil, leaving a little airspace and - depending on the food, a small hole made with a knife in the top foil - and baking, barbecueing, grilling (broiling) or even cooking in a frypan.