Waxy film on my Croton Petra

Question

I misted it with Miracle Grow and water once. After I first got it this summer, guess I shouldn’t have done that, huh.

Answer 1

Croton petra has a naturally waxy leaf surface.
If you think it's excessive then it could be an unusual protective reaction to the chemical fertilizer or something else like oil in the water.

Don't attempt to remove the natural coating, it's there for a reason, but you can clean the leaves of excess oil and dust.

https://www.gardeningknowhow.com/houseplants/hpgen/how-to-clean-houseplants.htm

Fertilize through the soil and root uptake to be safe.