A while back I posted about something maybe being in my chimney, well now there are 3 mice droppings around my fireplace. I find it strange because I have 2 house cats....am I best off letting the cats do their thing?

if they are house cats as opposed to outdoorsy cats they may not do anything with the mouse/mice.  You may be better finding a humane trap and catching them ASAP

Yes we use those humane traps as well and they do the job.  We also use peppermint oil, we sprinkle it around as it's supposed to be a deterrent.

Our dogs love mice they just look at them when they see one and then walk off, duhhh, LOL

my semi feral cats are rat hunters we have a lot of very shabby over grown messy neighbouring gardens one either side of me and then the ones behind, one of my cats goes on the prowl their finds a rat and brings in on top of the garden shed to kill it , its quite gross but then this cat was left to fend for herself a long time before i took over feeding her shes not as bad now but if you miss her meal time she will kill a bird within a few hours so i try to make sure shes feed same time everyday,
i think it depends on the cat, my old Axel was a more of a house cat i remember watching a mouse outside in the front garden once and it run right behind Axel as he was sitting looking up at me so i went down pointed on the floor where the mouse had been and he picked up the smell and went off to the next doors hedge and a few mins later he came trotting past on the pavement mouse in mouth he went to the garden at the end of our road and i assum he ate it yuk, but not the first time iv seen him eat a whole mouse, my cousins cat caught a mouse in her flat once and her cat played with it for hours never killed it at all i had to go around and get the mouse out of its misary in the end,

Mice will return to where they feel safe, so if you catch it in order to let it go again it will just come back :-( A humane trap will do the job quickly and cleanly, but you will have to be able to keep the cat(s) from getting their noses caught out of curiosity ;-)

I've just spent the last week catching mice in my kitchen (6 in total) as I have just had a new kitchen put in. I also have a cat that hunts every night (I do live out in the country) and he just wan't interested in catching these mice :-( I would put down a trap if I were you.

Or you could borrow my sister's JRT, they love to chase the mice.. Or anyone nearby who may have some, depends on what you want to happen to these mice, dinner for an animal or trapped and released elsewhere?

My dad has a jack russell. Might swap him a jack russell for a cat! lol.

Ive just hoovered up about 20 flies.....this is not looking good!

I used humane traps for mice and even though I checked them every day I always found the mouse inside the trap had died, I suppose of fright.  I didn't find them humane at all.

One of my Cairns killed two mice yesterday on our patio.  I was really upset, I like mice - outside, of course.

Well, I havent seen any droppings since I hoovered up so hoping its in the cats belly! :-D

my cat would not touch a mouse !   

we have pet mice and he is fine with them and sniffs and rubs his face on it :s 

one of my cats is a hunter every night this summer he has caught one, we can hear him playing with them on the front drive , he makes an high pitched meow I hate it when he kills them so my hubby usually runs out and grabs him if the mouse is still alive he shakes the mouse out of his mouth and brings him in ...I know you will all think I am crazy but cant bear it when he kills them....LOL  :)

My cat makes that high pitched meow when she has a gift for us.
She catches mice most nights and leaves them at the back door or on the kitchen floor.

I was sat in the lounge one afternoon last week, when she started to meow loudly from the kitchen,i went to see what was up with her and to my horror she had a huge slow worm on the floor....she was very pleased with herself.....i couldnt get out as it was by the rear door to call my neighbour to remove it...i had to ring him on the phone...and he came round and got it.
I dont mind mice but cant stand slow worms...they give me the creeps.