Need to remove the grill fron a trane XL1800 A/C to clean evap coil. How

You mean the outdoor unit?

Best way to clean coils on a train outdoor unit is to take the top off and hose from the inside out. For the indoor evap coil. If you take the front door off and remove the vent pipe. The coil should be able to slide out enough to get it good and clean. If the drain is not tightly plumed.

you mean the outdoor unit?

Yes, there are several plastic covers that appear to snap in place on the top; I don't want to damage them to get to the screws that hold the grills in place.

Take the top off and hose from the inside out.