I am having a problem with the door hinges on my kitchen cabinets. Some of them have become hard (some very hard) to open. These are European style, Grass brand and are of the type that is fastened to the side of the face frame. They have the quick release. They are self-closing and this action takes over when the door is within about 2 inches of being closed. They now behave is as if there was a very strong magnetic latch holding them closed. There are no latches of any kind. There is a tendency for the problem to occur on doors that are opened more often, and on doors close to the kitchen stove. If you open a door once then immediately a second time, it opens easier. If you close the door gently they are easier to open than if you close the door firmly. I took one door off, examined it, added a drop of oil where it looked like it might do the most good and reinstalled it. The door opened better after this. However, the next day, the problem was back, nearly as severe as it had been before, and after another day, no evidence of any corrective action.