We propose an approach to utilize idle computational resources of supercomputers. The idea is to maintain an additional queue of low-priority non-parallel jobs and execute them in containers, using container migration tools to break the execution down into separate intervals. We propose a container management system that can maintain this queue and interact with the supercomputer scheduler. We conducted a series of experiments simulating supercomputer scheduler and the proposed system. The experiments demonstrate that the proposed system increases the effective utilization of supercomputer resources under most of the conditions, in some cases significantly improving the performance.