When I started powerlifting in the mid '80s it was already pretty accepted practice in my gym. Either ammonia capsules or little brown bottles of "ammonia inhalant USP" (something like that). These days I use caps mostly, but I also keep little pill bottles with a bit of rag and a splash of ammonia and a few bottles of
Nose Tork. in my bag.
It's really like having a partner slap you in the face, but it doesn't leave marks. Also it really lets you breath as clearly as you've ever breathed for a few seconds.