When you look at the event screen you will see this.
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Dark tiles....not revealed yet, must remove a tile next to it using 1 of the 3 tool.
Lit tiles showing treasure........ jugs contain usual stuff, troops, medals, etc etc Plus daily reward. % chance of winning one of them
Icons on their own.........tile has been destroyed leaving treasure open to collect.
As shown above there is a brush ( use to remove a single tile that is lit ) shovel ( use to remove a complete row of vertical tiles. if there is a stone tile in the row, the shovel will only remove sand tiles between the stone and the edge of the row) as well as the gold icon ( needed to complete main reward ) and jugs.
The lit tiles that are blank contain nothing, the lit tiles with treasure can clearly be seen. Those are the ones you need to get.
Using dynamite on the area top right by the jug will open the 2 dark tiles on the right above and below the stone tile.
a brush on the idol ( bottom right ) will open the idol and reveal the tile to the right and below it.
Hope this helps folks.
One issue we had on beta was working out how and where to use each tool the most productively.
some people ( including myself ) thought you had to remove every tile but later worked out that lit tiles showing nothing were in fact empty.