Choice of litter & of flea preventative

Question
I'm thinking of switching to clumpable litter since so much less is needed. I have 2 cats & two litter boxes and I want to contribute as little as possible to the landfill. What do you recommend?

Also, are Hartz Flea & Tick drops as good as the Revolution product? The active ingredient of Hartz is phonothrin, while that of Revolution is selamectin. I am feeding 3 feral outdoor cats that I had spayed through a local program & I'd like to cut back on the cost of their care. The Hartz product is considerably less expensive than Revolution.

Thanks!


Answer
I am so sorry for the delay.  Apparently the request got routed to the wrong folder.. again, my apologies.  
As far as the litter box question, I would recommend a clumping cat litter made from soy.  It is a pellet type litter, low dust, relatively new on the market, very clumpable, wonderful odor control and absorbtion.  If this is not available, then any of the name brand scoopable litters will do.  They come in a variety of types to meet your needs.  Some are scented, some have baking soda ,some are designed for multi cat households to name a few.  As for the question about Revolution, that would best be answered by a volunteer who is a vet, or vet tech.  I am not versed enough to give you an informed decision.  I will say, on a personal note, that Hartz  pet products have not always had the best results not the best reputation.  I would see if there is another viable product.  Perhaps a vet can tell you more about your options.
Again, sorry this was late, but I hope this will be helpful to you.