I reproduce here a posting from the BGG forums:
"Oh what to do with the blank tiles? Yes one could cut and paste images from anynumber of places devoted to Carc variants, but if I did that the result would an unpleasing cut and paste job. So, what about keeping them blank? Several ideas come to mind. Here are several approaches that could be applied when a player draws a blank tile:
1)The player loses his or her turn.
2)The player does not place a tile, but scores points. This approach opens up several possibilities. The blank tiles could be deemed owrth a set number of points, say 2 or 3; or the first blank tile drawn is worth 2 points and the second one worth 3 points; add a 4 or 6 sided die and permit a player to roll for the number of points to be awarded
3)Permit the player to remove a meeple from the display. Again several possibilities are available, such as the player may only remove their own piece, or only remove an opponent's piece, or may any meeple (their own or an opponent's)
4) Permit a player to add a meeple to the display without playing a tile.
5) Permit a player to draw and place two tiles that turn.
6) This one is more complex, but use the blank in the same manner as the blank tile is used in Scrabble. Permit the player to either call landmark feature for each of the four sides or, only the sides that are matched to the display, therby permitting a subsequent player that plays to any open side to name the feature."
Some interesting ideas in there. I added one of my own (piggybacking off Treasure Hunt, I might add
):
"Another idea, by using 1 blank tile and a white meeple, is that you get control of the white meeple. This can deployed along with the regular meeples. Leave the tile in front of you so everyone knows who the white meeple belongs to. You perhaps could colour the other tile in another non-standard colour (meeples are readily available in white/orange/brown/purple/pink) or even mark one tile with a builder icon, one with a meeple icon. Control of a white builder or white regular (or even big) follower."