Need a trivet in the bottom of a black iron dutch oven? Twist a foil sheet into a wrinkled "rope" that can lift the pan off the bottom of the dutch oven.
The crunch foil rope also works to keep kabob skewers above the BBQ grill grate.
I use a version of this when roasting chicken breasts with a rub that will burn. After lining the pan with foil, I twist a foil rope, make it into a coil and place the breasts on top. The rub, BTW (actually more of a sprinkle), is 1-2 TBS of brown sugar mixed with 1-3 tsps of dry Italian dressing mix. Adjust to taste. roast/bake as usual. Throw away liner and coil...no messy. burnt residue to clean.
Oh, I also use foil to make a spatter shield around the pot when reducing a sauce, like spaghetti sauce that cooks for a few hours. Just take a length of foil or 2, crease and tear into 2” wide strips. crimp over the pot edge, joining as needed and make sure it will withstand the frequent stirrings. Again, discard after use. Spatter is reduced considerably. Same principle to prevent a pie crust edge from overbaking....crease the 2” length of foil and place over crust edge after 15 minutes.