Mr. CleanMagic Eraser Extra Durable Scrubber & Cleaning Sponge, 4 Count (Pack of 1)

Q: could this work for my Smartphone's screen? it has a small scratch!

I would not use it for your smartphone screen

Q: Is each eraser pad for one use, or can you rewet it and use it again another day?

You can use this several times. The contamination sitting on it may be the bigger concern. I know that you can put a sponge in a microwave wet for about 30 seconds to reduce germs. These I am not sure about. I have used the regular version of these and they fall apart very quickly and in my opinion are not worth buying. This version "Extra Power" is worth the money. they will not last very long if you use them on rough surfaces or sneakers.

Q: can you use on a self cleaning oven?

I’m sure you could to wipe off residue from the cleaning. I use these for cleaning everything. Hope this helps.

Q: Does anyone know if these are more abrasive and harsher on surfaces than the original magic erasers? Do they work better?

I will only buy the extra strength brand now. I think they work better and last longer than the regular brand. I haven't noticed a difference with scratching surfaces.