What can I safely put between my cast iron skillet and induction glass top stove to prevent scratches?

You could use a thin disc of copper...

Copper has a much higher melting point than does aluminum (1,984ºF or 1,084ºC vs 1,221ºF or 661ºC), is not ferromagnetic, and a thin (.025" or less) sheet should not have a profound effect on the magnetic field induced in the iron skillet.

I have not tried this method, but it is scientifically plausible as well as cost effective at about $25.

The copper surface could be sanded smooth and could be used in a similar way as a heat diffuser. It should get no hotter than the bottom of the cast iron skillet, since the induction 'burner' should not induce any magnetic field in the copper sheet itself. The only heating of the copper would be from conduction or radiation from the cast iron pan.

I don't know if it will work with your induction cooker, but I have used a very old and worn out sheet of silpat, silicon baking sheet. I have an older induction cooker and used the silpat to protect the cooking surface from scratches and from the food/oil splatter that happens so often when I cook. I have not had a problem as long as the pan you are using is induction ready and the silpat is pretty thin. But my induction cooker is quite old and perhaps this won't work on newer ones.

No, don't use paper or textile, they will char at meat searing temperatures. It is good for lower temperatures like simmering or sweating vegetables.

At that heat, there is not much in the household you can use. Very thin wood won't catch fire, but it will deform. Metal is problematic because it might be feromagnetic and get hot instead of the pot. Basically, what would work would be ceramic or glass, but you need a rather thin one (inverse square law, etc.), and the glass would need to be heat resistant. So, if you can find a really thin ceramic tile, that might work, but be a bit problematic in handling (easy to break). Slate would be a good material, and you can probably get it thin enough, but you will have to test if it doesn't scratch the glass by itself.

So, you will have to get creative. Maybe look in a lab supply store for something usable.

You can use some sandpaper to smooth the skillet out. However there is another problem, assuming as the metal heats up, some of the seasoning oil becomes liquid again, this leaves hard to remove stains on the glass cooktop.

I tried:

• parchment paper - it just scorched/burned.

• aluminum foil seemed to work, but wikipedia claims it can melt and fuse with the glass, so better safe than sorry.

• 0.5?? copper sheet, did not work. I don't know how the induction cooktop knows, but it knows. With just the skillet i pulled from the socket 2200w(220v), with just copper sheet 200w, with copper sheet and skillet on top 220w.

• 4mm fireplace window glass. Pulling 2200w and works fine. (I tested beforehand with stacking cards 4mm high and checking if the distance is too much).

If you put something between your pan and the stove it may not detect the pan if it is not in contact, and you may not get a good result.

I have an induction (hate it, it's like trying to cook on an ipad) and I have a lodge cast iron pan, I've had no issues with scratching at all. If your pan is really rough then I would suggest replacing it with one that is smooth, or smoothing down the coating on the bottom with an electric sander. You could spend more on a solution to save your pan than you would to buy another one.

Turns out that cotton doesn't ignite all that easily. I've been cooking steaks and burgers on my Lodge plate using a cotton kitchen towel! Works a treat, costs nothing. Grill plate doesn't slip or scratch. Easy to clean!

Wolf induction rangetop; have been using parchment paper for iron skillet. Heat range has not exceeded 4 dots (I call that "medium".) Scorching of paper ultimately leads to replacing. Seems reasonable and cost/effective.

Don't use newspaper. I tried it placing it on the burner to protect the cooktop as well as to catch spills and splatters. Though it did not catch fire, it did char and even got "ashy." Which I don't understand (how do you get ash if you don't have a fire?).

I thought the newspaper would be ok because the salesman had demoed induction by placing a $10 bill under the pot and the brought the pot to boiling.

I will also mention that cleaning up after using newspaper was not fun. The ink from the newspaper was scorched to the cooktop (but curiously not the pot bottom). I was able to get the ink off using the cooktop cleaner, but it took a lot of time.

I've used newspapers since (as well as towels), but only to surround the pots and pans to catch spills and splatters. I've had no charring or scorching incidents.

This makes me think that it's the weight of the pot on the burner that exacerbates a potential or real safety problem when using certain materials as a burner protector.