how to keep this from rusting again?

dear all

this piece was heavily rusted. i had to sand down the rust this means it's made of iron, right? but i found that parts of it looked yellowy. can anyone tell me what it would have been made of? i swabbed it down with Singer oil after i cleaned it cos i didn't have anything else handy
any advice welcome.

regards
phaik hooi

 

Very nice areca nut cutter!
Steel wool is better than sand paper (if it is what you mean by sanding it!) for metal. Oil is fine, but microcrystalline wax is said to be the best

 

Singer oil was just fine. It's an extremely light oil used to lubricate old sewing machines ...like the one I'm still using. If this is meant for food use, I might go for mineral oil instead, from a pharmacy.

 

noted tq! microcrystalline wax for better protection or mineral oil if using for food.