Razor strop paste, used in conjunction with a Strop, is an effective method of sharpening a "less than razor-sharp" straight razor. There are multiple pastes of varying grit sizes which perform differently, each intended for a specific purpose. The Red paste will restore the edge of a less than sharp blade. The Black paste will finish and polish the sharpened edge.
Sharpening pastes should only be used on a leather strop reserved for that purpose and various grit pastes each require their own strop to avoid cross contamination.
This particular paste comes in a soft block form and should not be stored where temperatures might exceed 80 degrees (F) to avoid melting into a liquid.