I stupidly put Castor oil on the front down tube during the winter because the cold was causing problems folding. Instead of making it easier it made it much worse to fold. I've tried degreaser, chain lube and just plain cleaning with Dawn. It has helped a little but I still have to use my Swiss Army Knife large flat screwdriver to open up the part that front tube slides through to go under the main frame. I'm thinking of removing that piece on the main frame that folds the tube down and cleaning it out but I hesitate to do so if I can find a cleaning solution that would help remove the grit from the front down tube . Any suggestions ?