Systematized information about standardizable parameters and methods of monitoring mechanical impurity contents in lubricant coolants, industrial and motor oils, and gasoline is provided. Considering that in most cases metallic impurities possess ferromagnetic properties, magnetic methods are preferred for monitoring iron-containing impurities. The basic aspects of the relatively new experimental-computational method approved for a number of fuels and lubricants, which, contrary especially to the experimental method, allow more accurate monitoring of ferroimpurity content, are expounded. The suitability of the model of exponential ferroimpurity absorbing screen for this monitoring method is confirmed with reference to gasoline, diesel fuel, and industrial and motor fuels. Based on the results of the proposed magnetic monitoring method, a notable demerit of one of the most popular variants of magnetic monitoring used for ferrography is pointed out.