Cleaning the Anchor Sleeves
By cleaning the anchors when you install and/or remove the cover, you will save yourself a lot of trouble and ensure they continue to work smoothly.
They don’t require much care. Just, use a can of compressed air to blow out dust and dirt. Then apply some lubricant like WD-40 or silicone to the threaded anchors. When you remove the cover be sure to screw all of the anchors flush. Not only will this keep the anchors working well, it will keep you from tripping on them or snagging the cover.