AZ is a bit hot lately, so running AC's more than usual.

Just noticed no dripping out the drain pipes, but then again has been
a bit dry at 10-12% humidity so maybe no big deal. But remember Jim
Thompson, and others posting about spider nest build up in pipe or
slime mold clogging pipes and not noticing until catastrophic, like
water is dripping through ceiling.

Don't want to get that far.

So how to make certain the AC drain system is clear?