turtle.cleanInventory = function(mod)

    -- turn around, dig 3 forward and drop all shit here
    turtle.turnRight()
    turtle.turnRight()

    turtle.saveDig()
    turtle.saveForward()
    turtle.saveDig()
    turtle.saveForward()
    turtle.saveDig()

    if mod==0 then
        turtle.saveDig()
        turtle.saveForward()
    end

    turtle.saveDigDown()

    for i = 1,4 do

        turtle.select(i)

        -- drop all but one

        --turtle.dropDown( turtle.getItemCount(i)-1 )

        for j = 5,16 do

            turtle.select(j)

            -- compare to  good
            if not turtle.compareTo(i) then
                -- drop all trash
                turtle.dropDown()
            end

        end

    end

    -- go back to original pos

    turtle.turnRight()
    turtle.turnRight()


    if mod==0 then
        turtle.saveDig()
        turtle.saveForward()
    end

    turtle.saveDig()
    turtle.saveForward()
    turtle.saveDig()
    turtle.saveForward()
    turtle.saveDig()
end