AutoTrash

local inv = peripheral.find "manipulator".getInventory()
local dir = "south"
local drop = {
    ["minecraft:concrete:0"] = true
}

local function toname(i)
    return string.format("%s:%d", i.name, i.damage)
end

while true do
    local contents = inv.list()
    for slot, item in pairs(contents) do
        if drop[toname(item)] then inv.drop(slot, 64, dir) end
    end
    sleep(1)
end