If you clean your cutters immediately after use, especially if you have been cutting resinous softwood, the resin will still be fresh and soft and WD40 on a rag will bring them up clean and shiny. Not only will the cutters be clean, but the WD40 will protect them without the need for a separate spray.
Important: if the cutter has a bearing, remove the bearing before using the WD40, which should never be used on bearings because it will wash out the bearing’s built-in lubricant.
The pictures show a resinous cutter before and after treatment with WD40. If you leave the resin to dry and harden you will probably have to use a stronger solvent to clean the cutter, followed by a spray or wipe with a lubricant to protect against corrosion.