Chemicals and solvents on a plane
Identify the chemical before packing it
At a US airport, a small container does not make a hazardous chemical an ordinary carry-on liquid. Read the exact product label and, if the contents are unclear, ask the manufacturer for its safety data sheet. Section 14 gives transport information; FAA PackSafe explains why a product regulated as dangerous goods usually cannot travel in passenger baggage.
Chemicals forbidden in both bags
The FAA forbids chlorine, liquid bleach and flammable turpentine in carry-on and checked baggage. Spray paint is also prohibited in both bags. These are chemical and fire hazards, so the ordinary 3.4 oz (100 ml) liquids allowance does not apply. The FAA's examples distinguish these products from permitted toiletries and some nonflammable paints.
Fertilizer and look-alike household products
TSA lists fertilizer as prohibited in both carry-on and checked bags at US airports; repacking it in a smaller pouch does not help. Plain potting soil, a detergent without bleach and paint marked nonflammable need their own assessment because their contents differ. See oils, detergents and aerosols for other household products. If you depart from another country or make a return trip, check that airport's rules separately. The TSA item list gives the US decisions for fertilizer and spray paint.