This is Paes 164 and these are a few quick tips on how to clean your graffiti tips. First and foremost when you're done flip the can upside down and spray until you kind of clean out the nozzle. Ain't nothing more a pain in the butt than when you are in the middle of a piece and you run out of tips.
Now, if you are going to be done for the day and need to come back with those same tips the following day simply get yourself a cup of rubbing alcohol and soak the tips in there. It will keep the goo and paste of the paint soft enough that you can come back and use them again within 24 to 48 hours. You can also use a little bit of paint thinner but that's not something you want to soak in because you're going to end up damaging the plastic of the tip.
Also, you'll notice residue build up on the tip, scrape it off. If you have to go back and attach it to the spray paint can flip it upside down and spray it once more, that's going to be the only way you are really going to save that tip. Keep that in mind when you start your mural so you don't run out of tips and you can complete it.