These solutions are prepared from a single source (one refinery) product. The weathered materials indicate the percent weight loss from the original material. Samples of regular and premium grade unleaded gasoline were collected, then blended in equal volumes.

There are four general types of mineral spirits, classified according to boiling point range (BPR):

• Type I (Stoddard solvent) BPR 149–182°C
• Type II (high flash point) BPR 177–196°C
• Type III (odorless) BPR 149–196°C
• Type IV (low dry point) BPR 149–174°C

We prepare our mineral spirit solutions from an equal volume blend of Type I, II, and III mineral spirits.