The study presents a comparative thermodynamic analysis of degraded C15-C50 grade crankcase oil (DCO) and paraffin thermal storage (PTS) as heat storage materials in solar drying. The goal is to convert DCO from waste to a useful product in solar drying. The assessment was based on drying efficiency, energy and exergy analysis, sustainability assessment and CO2 mitigation of each solar dryer. The difference in drying efficiency between the dryer with DCO and that with PTS is less than 1.5% while the difference between the specific energy consumption is less than 9%. In contrast, the difference between the dryer with DCO and that without thermal storage is 24.2%. The mean exergy efficiency ranged between 41.6 and 49.9%. The values of the waste exergy ratio (WER), sustainability index (SI) and improvement potential (IP) for the three dryers ranged from 0.00 ≤ WER ≤ 1.00, 0.00 ≤ SI ≤ 34.56, 0.00 ≤ IP ≤ 2.68 kW. Using these dryers instead of diesel, grid-based electricity or coal-powered dryer will limit a maximum of 5792826 tons of CO2 from the atmosphere.