The most effective type is hard to find in California. It will knock just about anything out.
You can use regular vinegar or cleaning vinegar (more acidic) but be careful!
If you are using anything stronger than the regular type you buy in a grocery store, make sure you are well protected (mask, gloves, eye protection, etc.).
So yes, it works alright and a lot of landscapers use it to get rid of weeds.
I poured some on the power meter outside and dandelions were growing in and outside of it.
Within a few days, they were all dried up and gone for the time being.
I'm giving up working in the yard. I'll leave it up to the new landscape company that I just hired (twice a month at $60/visit). My Greenworks corded mower is on its way out and a new 100 ft. cord is needed. I don't care to invest much into it as it is what it is ... ok for some things but a large yard ridden with weeds =
I'm in no condition to be doing this type of work anyway, but the calli lilly thing freaked me out good so I'm done!
Best of luck and I hope the vinegar idea(s) help!