The time and expense concerning our product depends on the condition of place and frequency of damage, of course earlier measure can cope with the problem most cheaply as a solution. However, you have better to understand and consider the best solution about current excrement pollution situation considering the Action Pattern and the example of a measure against pigeon.

               The Action Pattern of a Pigeon
Pigeons Rest case (Mr. Rest.)
They do not make a nest in your place, of course you can't find in the night but come during the day time. The problem is still very small, but we advise some measure coming near future.
Pigeons Stand-by case (Mr. Stand-By.)
If the pigeon like your place ,some times they stop at your place and wait for their friends to fly some where together, every day they repeat this one up to the night.
Pigeons Sleeping case (Mr. Sleep.)
Pigeon still not yet made any nest in your place, but they come every night, they like your place, your place is already one of their territory, this situation easily change to (Mr. living). You must consider quickly measure to protect the place from the pollution of pigeon.
Pigeons Living case (Mr. living)
Now the matter should be settled urgently. Quickly take excrement out and clean the place ,we must fight against their powerful instinct of homing and territory consciousness. The place which pigeon likes, for e.g. surrounded on 3 faces like corner, around exterior unit etc. Anyhow you must try to let them go, lets go briskly, even though you do some measure against it, pigeon still stop at a handrail etc. and the situation will continues when it try to find and returning to nest, now it is necessary to do counter measure to prevent invasion of pigeon completely.