Not all acrylics are created equally.
You shouldn't clean Acrylite, Plexiglas, Lucite, Optix, Polycast, Chemcast, Acriglas or Excelon (brand names for acrylic) with isopropanol, ethanol, methanol or acetone.
See this link.
Perspex, on the other hand, can be cleaned with isopropanol, soap and...