Sorry if this question doesnt belong here. I have no clue of what I'm about to ask. 

I want to know, if possible, how to induce negative/positive charge on objects inside recipients? What I want to achieve is this:

Say plastic recipient A have a liquid and some metal objects inside.

We also have recipient B with the same caracteristics.

Now I want to have positive charge on **everything inside** recipient A and negative charge on **everything inside** recipient B **without** dropping a cable inside each recipient.

I already have positive and negative charge being supplied on different cables. I want to know how to induce the charge wirelessly.