Knife Care
Carbon steel is a reactive material and will over time form layers of oxides. The patina will be unique to your history with the blade, to what and how you have cut. It does require some conscious care to ensure that your blade does not rust; primarily entailing:
Keep it dry
Wash your knife once you have finished cooking with warm, soapy water and then try with a towel or cloth. Do not leave the handle or blade wet
Oil the handle
Occasionally apply a natural oil to the handle to maintain moisture resistance and vibrance. Mineral oil is a good, food safe option
Sharpen regularly
To maintain performance, sharpen when necessary. Ideally use whetstones or other fine hand stones
Never go in the dishwasher
Even if your knife has a stainless steel blade, never put it in the dishwasher. It is a highly corrosive environment and will damage the blade and handle material
Do not cut on hard surfaces
Cutting on hard surfaces such as ceramic plates, stone or glass will very quickly dull a steel edge
Do not cut frozen or excessively hard foods
Be aware of what task your blade is engineered to perform. Thin, fine edges are not intended to cut frozen or hard food, such as bone, and are likely to bend or chip
Store Carefully
Do not, for example, place uncovered in a cutlery drawer. Ideally, have a magnetic knife rack or stand