Removing/Installing Andersen
double-hung windows have built-in interior grommets for easy grille removal and attachment. To remove grilles, carefully pull the grilles away from the sash grommets, one at a time. To install grilles, start at the bottom of the sash, snapping them into place as you work your way up. Brand new windows may have thin pieces of plastic covering the grommets. Drill or punch out these plastic pieces with a screwdriver, small drill bit or a nail set (Fig. 16). You may have to bow the grille slightly as you install it, but excessive bending may damage it. Take care to avoid catching your fingers under the grille during installation.
You can read more here.. It is in PDF format. Information loctated on page 8 and 9
http://www.andersenwindows.com/servlet/Satellite?blobcol=urldata&blobheader=application%2Fpdf&blobkey=id&blobnocache=false&blobtable=MungoBlobs&blobwhere=1112109285558&cachecontrol=5%3A0%3A0+*%2F*%2F*&ssbinary=true
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Handywoman
Remodeling & fixing things from Drywall, Flooring, Electrical, appliances for 20 years