I started reading a book called the Urban Primative today and the Authors provided an intresting prospective in saying that energies and Gods could be accessed in an urban setting, and a Pagan could cast spells using tools and the world around them rather then seek out a more woodsy, rural setting that to some of us is in large part inaccessable.  Do you know anyone who has practiced in this way?  Keep in mind, the others do not poo poo going into the woods or following what is seen as tradition.  I think they tried to give Pagans who couldn't go all out, or enjoyed the vibe of a city a way to observe and honor the gods.  They even mention Psy-Vamps. 

http://www.amazon.com/Urban-Primitive-Paganism-Concrete-Jungle/dp/0738702595

I do not practice Wicca or magic, so this only a layman's opinion. I would think that things used in magic are tools that the practitioner focuses their energy on. So changing the tools should be ok as long as the focus is not changed.

Oops! Forgot my wand, can't find a stick. Aha, I have a pointy thing on the end of my hand....

Dropped my chalice!! But if I curl my fingers like so......

People get too wrapped up in having the 'right' tools.

Use your imagination, it's the intent that matters.

Magick comes from the focus of the practioner's mind and Will. The tools are just a focal point for the conscious to tune its self to the subconscious. ( and yes you finger will work just as well as a wand, as long as you don't mistake the finger for the object of your intent )

There has been alot of emphasis on "getting it right" these days and less on "doing it right". Magick is manipulation of the energy flow, how can you do that if you are paralyzed by not having the right tools?