The present invention provides methods for decreasing amounts of metal ions in liquid materials and in porous solid materials surrounded by a liquid, by utilization of sequestering agents that form complexes with said metal ions as well as methods for removing and optionally recovering said metal ions from the complexes. Timing of valve closingopening and use of an air supply system may enable engine operation according to a Miller cycle. The DCDC converter is arranged for converting an input power to a DC power according to a control signal. The control device, the low-pressure switch, the display elements displaying the dust flow, and a battery compartment for receiving the batteries are arranged in a housing formed on the upper side of the tubular connection part. In the method, combinations of concatenations are compared to chronologically preceding concatenations. Each finger has a plurality of retainer teeth formed thereon.