Like 15 years ago I had this fleece where whitetails would peg me and spot me from 75 yards away and just stare at me when it was getting very dark. I hunted in a place where I'd see multiple deer a day so it wasn't a one off thing. They'd generally walk right under me. Every single time.
I'm super nerdy, so I dug deep in scientific literature. There's a study (probably more now), that indicates that some deer species can see into the UV spectrum.
If your camo is cheap (that piece was not...realtree something or other), it can be made with UV brighteners.
So I'm really careful about that now. Oh yeah, if you want to know what soap to use...look at the Army's list of non UV brightener detergents. I use 7th generation non scented.
I keep my clothes in totes. During a hunt or if I'm hunting locally I'll just keep this in the tote: I'll cut some branches off a stinky plant that's common and put it in the tote as a cover scent. Generally I go for red cedar, balsam fir, big sage, or engleman spruce. I've been known to use corn as well.