Acrylic is very fragile, especially when exposed to cold.  Also, extended exposure to direct sunlight or heat can cause warping.
Alcohol and other chemicals and solvents can crack, degrade, or even destroy acrylic.
Clean with warm purified or distilled water and germicidal soap.  Most acrylic cannot withstand the pressure and high temperatures of an autoclave so it must be disinfected rather than sterilized.
Use your hands or warm water to heat an acrylic piece first before attempting to using it or it could snap or crack due to brittleness.
Acrylic can be scratched easily, so check the condition of your jewelry regularly.  Avoid the use of tools.  Handle and store your acrylic jewelry carefully.
If you screw on an acrylic threaded end too tight, you can crack it or cause the threads to come out of it.