A clamping-type knife sharpener is designed with anti-rocking blade holding capability. The devices, systems and methods include a hydrocarbon absorbent material, and a structural element configured to hold the hydrocarbon absorbent material within a clean air tube of an internal combustion engine. With this method, phenotype classification of lipid can be easily performed. In order that the screws can be used in situ for very different lengths, the threaded section and the head are designed as separate parts.