Remove the plexiglass from the mounting structure, if possible. If you cannot remove the plexiglass, position it to gain as much access as possible.
Protect the area around the plexiglass insert from water or other compounds, since during the cleaning process the plexiglass will not act as a barrier to these elements. Tape a tarp over the plexiglass insert to keep everything clean.
Organize the polishing pads included with your restoration kit, from coarse to fine. The pads may be labeled, so check for any numbers or writing on the pads for starters.
Apply the restoration compound to the coarsest pad and work the compound into the crazing on one side of the plexiglass. Move through the pads until you end up using the finest one.
Switch to the opposite side of the plexiglass and follow the same procedure. Review the plexiglass for any remaining crazing and follow the same procedure until the crazing is gone.