A/C O-tube keeps clogging up

About a year ago my A/C started to lose Freon and about 3 months ago I finally decided to replace the compressor (seal was leaking) along with a few other parts and I noticed the orifice tube was caked with something But it still worked. Now that I have "fixed" the ac, I keep losing freon out of the pressure relief valve because the orifice tube keeps cloggin up. What gives? I cleaned the system before putting in the new parts and blew the hell out of it with the compressor.

Any ideas where to look, please help...