Is the question "can I use a pair of metal pliers in my marine tank that I use for other stuff and keep with my other tools without causing damage to my aquarium"? If so, the answer is yes in theory, but in practice, I think it depends a lot on what you do with your tools. If they mostly sit in a box collecting dust (no judgment; that's what mine do), I'd feel much safer than if you use them to do plumbing or welding work, for instance.
If any of your tools have been exposed to any harsh chemicals or acids, for instance, I'd be concerned about chemical transfer and probably not bother. If you're really set on doing this, though, I'd give them a thorough washing. First just in tap water to get rid of the dust, and then dry with a microfiber cloth. If any visible oils or gunk come off beyond dust, or there's any visible rust, spotting, or deterioration on the tool, I'd stop there. If they are dusty but otherwise pristine, I'd give a wash in treated water you would feel ok putting in your aquarium and then set to work.
That being said, it would still be safer to have a dedicated set of tools for just your aquarium, and that's what I'd recommend. I have a scrub brush that I use for washing dishes, for instance, and a separate one for scrubbing liverock. Just because I could clean the scrub brush well enough for it to do both doesn't mean I'd feel safe doing it.
