Must remove all joints are at a minimum of at least a half inch with a grinding wheel if they’re hard to get out then you read joint them I think the easiest method is a grout bag with semi wet cement definitely use a fine sand and a good type S mortar I do have additives to make it a little sticky for better bonding.
Do not worry a little more gets on the stones try not to get too much on the stones but it’s not a big deal either way let the cement dry until it’s tacky enough to where you press to jointer to shape it it doesn’t splatter go on all over the place you wanted to be like Oreo no chocolate chip cookie dough when you make a little balls u want it to be semi dry .. Than you do all the left and right up and down you shape them with the design of your choice you can shave them flat to the face of the brick with a flat pointer I can shave them with
Round jointer they also have a jointer with a little line in the center we can do a sloppy joint what you leave the joint on shaped get the name of it but it says style people use Rockaway but it’s just different joint styles for other applications after you join them and shape them you allow them to dry some more pretty much all the way dry maybe about 30 minutes 40 minutes can you hit them with a brush removal of snacks and stuff on the stone if there’s still some stains you can take a wet sponge and give a quick wipe try to avoid touching the joints themselves most of the stuff to knock off on its own didn’t mess with it and you left it alone like I told you because if you stop messing with it try to clean it while it’s wet here’s to Stone and it’s a lot harder to get off and dries…
I always like to wait some time couple weeks to a couple months until she do it the next day if you do it easy and give it a light chemical best to remove any stains of white or efflorescence you break it down you don’t put a pure and put them muriatic acid are all the chemical in a bucket with a sponge and ask if you do want why dip the sponge and clean it One wipe on both sides of the sponge
Do not do any more than that because you won’t notice it till later but you will spread the stuff all over the place only one Of wipe and rinse . Repeat until everything is clean and allowed to drive keep everybody off the patio for a day or two in the power wash do not scrub cement take some time to cure but you can walk on it gently good luck with your new patio Hope this helps

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