Candidates and job vacancies may remain for long periods without real opportunities in Recommendation Systems (RSs) for online recruitment. We refer to these scenarios as the Matching Scarcity Problem (MaSP). We formalize the MaSP and propose a strategy to identify candidates and vacancies suffering from it. We also propose five heuristics, which suggest changes in CVs and jobs descriptions, to mitigate the MaSP. The best heuristic was able to reduce up to 50% the number of CVs and jobs suffering from MaSP.