This article studies the effectiveness of dust extraction of mildewed surfaces used as an alternative method to the currently used curative treatments. The work done on different organic supports forming a graphic document (paper, leather, textile), had been contaminated by two mildew stains. The dust was extracted after a different drying period and then re-cultivated. The results show that the effectiveness of dust extraction depends upon the physiological condition of the mildew. It is difficult to extract dust on fresh mildew, as the mildew gets crushed, thus leaving behind stains. Moreover, contamination increases when these supports are in conditions that are favorable to germination of spores. These uncertainties decrease as per the drying duration. Dust extraction becomes easier when the duration is longer and the supports have fewer stains. Whereas, on re-contamination, the mildew is more grown than at the time of initial contamination.