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If the lanolin cream is getting too hard, and there is some airspace within the tube, you can dribble several drops of mineral oil into the tube, replace the cap and knead the tube to mix the mineral oil into the cream. The mineral oil will soften it and make it spread a little easier. For what it's worth, I don't like the stickiness/paste consistency of lanolin creams. K-Y jelly works fine and washes off with water.

I believe that mineral oil is the main ingredient in petroleum jelly--a product we are advised to not use with silicone.
Of course, you are referring to a small proportion; but I would mix up a small batch in a little cosmetic jar--just in case.