Clogged AC Evaporator line

I have a 16 year old high efficiency central air where the evaporator condensate feeds into a pump to be removed. This week for the second time in abput 4 months the pvc line coming out of the evaporator clogged. There is a cleanout where I ran a brush through to clean it and it fixed the problem. But I have to think there is junk somewhere in the unit that is being dislodged
I'm assuming probably somewhere "downstream" in the vertical pvc line feeding into the pump there is some junk. Is there something I can pore in the cleanout to flush any possible goo out?

Not sure, but I will tell you that one time on mine, I ended up with a woody fungus growth that essentially blocked the outlet...needed to be reamed out before I could pull the rest out.

possible evaporator coil cleaning

A cheap fix would be clorox solution if you can put up with the smell and don't drop it on the rug. Sounds like the coil may need cleaning along with the drain pan. (you been running the unit without a return air filter?)We use to use a chemical call Calgon to clean the evaporator coil with a soft brush but I don't know if they still make the chemical or not I am sure there is a replacement by now.

Use a shop vac to suck it out.

John