Why do I have to do a science experiment with lemon juice to know if the knife is stainless steel or carbon steel? Why is it not imprinted on the knife itself so I can verify before purchase? I just want my new knives to not rust after one use. My old knives that I have had for 14 years have not rusted at all. I had to get new ones because water was getting inside the handles of the old ones and would take forever to dry.
Whether stainless or carbon (or ceramic), you should clean your knife as you work. Doing so will prevent it from rusting and build a patina (if carbon) which will further help prevent rust.
If you want to force the patina, this video by Knifewear might help.
Sharp Knife Shop has a good video about patinas.