Omg I'm glad you posted this - I moved recently into an apartment and there are burrs here too !! I never had this problem with my yard ...if and when I'd find a little 'burr' plant I used to pull them right up .....I can't do that here cause I can't even find them
I avoid the known places here that has them and the girls walk mostly on the sidewalks - I'm hoping burrs go OUT Of season soon so they can walk on the grass again.
I do the same as Gizmos mom- seperate the hair 1st then gently pull them out but they ARE Sharp ....I always check first under the arms or on their little tummies - those need to come out right away - I stepped on one and it felt like needles...not to mention - one cut my fingers when I first moved in.
Back when the girls had a bunch of them - I retraced my steps mentally and no longer walk that way - within a few weeks I pretty much figured out which spots are full of them and what isn't... but I still check my girls every day before I leave for work
These nasty things HURT.