I pit interfacing that cannot handle chlorinated water. Come on, folks, don’t you think that the shirts you are making might end up being washed in municipaly treated water, and chlorine or bromine are commonly used for such treatment? Let’s put two and two together here.
That is all.
Interfacing is that stuff sewn/fused behind fabric to make it stiffer, right?
Yes. Crap quality interfacing stains rust yellow when it is washed in chlorinated tap water, which has left me with half a dozen new white dress shirts with discolouration on the tips of the collar points. None of the the local cleaners de-chlorinate their water, and I do not want to have to go to the bother and expense of installing such a filter at home, so every once in a while I end up having to return a batch of shirts due to poor quality interfacing.
Serves you right for buying such complicated shirts.
I advocate returning to the toga.
I’ve never heard of interfacing that can’t stand chlorinated water. I sometimes sew my own clothes and I use the cheapo-type interfacing that comes in the little plastic packages, and I’ve never had trouble with it. How odd.
Toga! Toga! Toga!
Wait…don’t you work from home? I thought that meant you spent all day in your bathrobe and house slippers after getting up at 11 AM and putting in a tiring 4 hour day… 
Google interfacing chlorine stain.
In the early 1980s I took some lessons in chiton making from a person who worked at the Royal Ontario Museum, bought up a large number of old sheet from the Sally Ann, and then spent many enjoyable hours fitting the Pi Phi’s. Never had so much fun earning pin money!