In view of the permanent increase of the municipal solid waste incineration (MSWI) residues amount, the numerous attempts to find a way of their recovery are undertaken. In the paper the idea of the recovery of the MSWI residues in Kłodawa salt mine is presented. The idea is to fill-in, close and/or backfill the underground excavations with self-solidifying mixture prepared on the basis of MSWI grained solid residues. Two techniques are proposed: 1) hydraulic backfill technique (HBT) where the mixture is prepared in the surface installation and supplied down into the underground openings through shaft and the pipelines and 2) dry waste technique (DWT), where dry grained waste is dropped into the mine by pneumatic pipeline transport, then supplied to the underground mixture-preparing-installation and pumped as a thin liquid or paste into the target excavations. The description of the idea of the technology is preceded by general characteristic of the hardening backfill in underground mines and by characteristic of MSWI residues, drafted on the basis of the literature review.