Air Conditioning - Cleaning the A-Coil on Central AC

I recently had a new compressor unit installed on my central heating/AC unit. When the installers were checking the airflow, they removed the filter. When they finished, they forgot to put the filter back. This was a year ago. Since then, we have been traveling most of the time and had someone watch the house. I asked them to keep check on the filter and replace it if it showed any dirt. Well, they forget to check it. Now I'm back home and when I went to check the filter, I discovered that there was no filter in the unit. It has been running for about a year with no filter and I am sure the A-coil is pretty dirty. I called the installer and he said that the entire A-coil assembly must be removed to get to the coil and clean it. This is going to be expensive. Is there a less expensive way to do this? Can it be accessed to be cleaned by cutting some sort of door to get at the coil? Is there any other way that I'm not thinking of?

Thanks for the help.

Daryl