I wanna fix couple things at home (seems like it's a never ending
saga)

1) I have a cooktop (as oppose to gas range) which works decent but
it's old and paint is coming off and has plenty of stain. I don't want
to replace it because then my wife wants to get a matching oven. So I
was thinking to paint the top surface and 4 grates (I can't get the
same grate from manufacturing since they are obsolete). I cleaned
grates with Ammonia but they still don't look good.

I searched home depot for metal spray paint but all paints were for
cold surface. Is there any paint out there that I can use to pain top
of cooktop and grates which gets pretty hot?

2) I wanted to paint/stain my kitchen cabinets. A few of the cabinet
door have a heavy stain. Should I resurface them with glass paper and
then stain them, would that work?

I would really appreciate your suggestions.

Thank you,
Steve