removing plastic "phoney colonial" grids from Kinco windows - how? anybody know?

for cleaning purposes, would some kind soul please tell me how to -remove- the decorative muntins (aka the plastic "grids") from the window sash in Kinco aluminum-framed single-hung "series 40" windows?
grids in question best illustrated in the rightmost top and bottom images at
note kinco's "asp-contact them" online form is non-functional... :-( also, their website has -zero- info on this subject, and, in fact, doesn't even tell how to remove the sliding sash and screens (which I _have_ figured out by now)
all kinds of tree krap, pollen, dirt, mold, and small organic debris is behind the grids, especially near the sash edges/bottoms, between the glass and the grids, plainly visible from indoors...not overly 'scenic'
do these rigid plastic grids "unsnap" or unfasten from the window sash? (they aren't glued to the glass). if so, the removal method for them isn't what I'd call "immediately apparent" how's a guy supposed to clean hind= the grids, especially near their edges? the best I can manage so far is inserting a small thin wooden wedge mid-grid, to give some small clearance*, but I'd -vastly- prefer to remove them, for cleaning...
note: I'm =NOT= asking how to remove the moveable single-hung SASH from the window FRAMES here...
*note the nuisance decorative grids are VERY rigid plastic =indeed=, so, after I got about a quarter-inch clearance between grid-midpoint and glass midpoint using the wooden wedge, I didn't want to insert a thicker wedge, and risk glass breakage, or grid breakage...or both :-\. also, there are no screws, "unclip push-tab ears" <or any other fastening methods, for that matter> visible at grid edges, outside, or inside, either...
thanks much in advance for info
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