Kind of depends on if it's hot or not (Antibalas last year was real toasty), but if you bring one of these filled with water for your group and people around you that want it, it's always a hit.

https://www.amazon.com/Chapin-20002-Fertilizer-Herbicides-Pesticides/dp/B0039EEN0M/

I think it's usually a silicone based lubricant, used to keep the o-rings and seals from drying out.

It will probably be fine though, just try to rinse as much of it away as you can before using it on the frogs. I've been using garden sprayers for years, and they always come with some kind of lubricant on the pump parts. I just wash it really well, and run a couple tanks through just spraying it into the sink to clean out the internals, and I've never had any problems.

This is the one I'm using now if you're interested. I also went through two exoterra sprayers in less than three months, so I started getting them at garden centres and I have no regrets.