system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does Vaseline or Petroleum Jelly makes your hands or skin much smoother and softer even if it has no moisturizer content?
gpt
Because it's basically grease. 

Grease makes sure moisture doesn't escape the skin.

Thick grease smooths stuff out by covering imperfections. 

Grease helps the skin be protected from other things and grow new healthy layers a bit faster. 

And since it's not organic grease in the sense that it's not stuff living beings make now, most lifeforms have a tough time digesting and absorbing it, hence why it lasts so long on skin.