Flushing evaporator

[Jason94sport]

I have to replace all my ac system. I have a compressor, lines, accumulator orifice tube & condenser all new R134. The evaporator is from an r12 system(93)
How can I flush just the evaporator out?

 

[Jason94sport]

Bump,
Will a high pressure air hose work well enough or do I need a flush kit? Only need to flush the evaporator.