Inexperienced chemists (such as undergraduates) can provide much amusement (and bewilderment) below are some examples of naevity / ignorance: Students were instructed to run TLCs in 40-60°C petrol: The student submerged their TLC plate in petrol, which they were heating at around 40-60°C... Students were instructed to chromatograph the product on silica with petrol/dichloromethane (10%). The student had taken this to mean a 10% emulsion of petrol/dichloromethane with water... Student was attempting to crush a NaOH pellet with the end of a Bic Biro, holding it on the bench with his (unprotected)fingers. Efforts to do so repeatedly projected the pellet across the bench. Why? He wanted to weigh 250 mg... (the mass of that pellet: 245 mg)  And one from industry: A chemist had developed a TLC system using a mixture of methylene chloride and dichloromethane... Any more gems... Les.Oates@angelfire.com