All quality acrylic sheets are covered the protective films to avoid scratches during shipping. The paper masking should be left intact during storage to minimize scratches. Remove the protective coating from acrylic sheet until you need to use it (just like the right video shown). However, if you won’t use it often after removing the protective films from acrylic sheet, covering a soft clean cloth can protect it away from scratches as well.

The other thing need to be noticed about acrylics is that they are easily stained by fingerprint，grease & oil. However, it is easy to clean these with soft cotton cloth or paper with neutral cleaner (such as a solution of water and a small amount of liquid dishwashing detergent). Never ever use cleaners containing ammonia, sandpaper or rough pads on acrylics, because you will keep the fingerprint, grease & oil stay but with more scratches. For daily care & maintenance of acrylic sheets, just polish lightly with cotton flannel, then wipe with a damp cloth to help eliminate electrostatic charges that can attract dust particles. Notice that soft clean cloth with isopropyl alcohol can effectively wipe the fingerprint, grease & oil and sticky on acrylic sheets, however, some designs on acylics can be soluble in alcohol and detergent-water, such as designs on acrylic wedding invitations or acrylic signs, please don’t use alcohol to clean the designs’ part on acrylic sheets. And for the sticky substance, like protecting most materials, please put acrylic sheets as far away from it as you can.

Source：acrylite

Like most materials, avoid storing acrylic in extreme temperatures, above 100-degree Fahrenheit. Don't store acrylic in direct sunlight in hot conditions. This can cause the acrylic sheeting to expand and reform (by acplasticsinc). Do not store acrylic sheets near spray painting booths or expose it to other solvent vapors which may penetrate the masking and damage the sheet surface (by redwoodplastics).

For big size acrylic sheets, such as acrylic signs, they should be stored vertically or in special racks where the sheet can lean at an angle of approximately 10º. For vertically storage, acrylic sheets should be in special racks. If Acrylic sheets are stored horizontally; it must not be allowed to sag. If various sizes are stacked horizontally, the larger sheet should be at the bottom to avoid unsupported overhang (by acrylite).

Generally speaking, for small acrylic invitations, you just need to put them into storage cabinets or hard boxes in your basement, and without frequently moving and extra conditional actions (such as strong press, bend), they can be stored very well.

Source: gilbertslettering