Auto parts stores carry 'cap less funnels'. I keep mine in a capped water bottle- so easy to take funnel out of it and back in after you do your additive. I also have 'wet wipes' available for any clean ups. Works for me- but if you have kids you don't want them to mistake container 'for a water bottle' - so I keep mine in garage next to my additive container as reminder to bring with me on fill ups.