Winter muck... there are a couple of solutions to this. To reduce spray from the front wheel, I have seen bikes fitted with a simple flat plate (aluminium or plastic) fixed on the down tube, using the bottle cage fixing screws. It is the sort of thing that could be made easily from scrap materials. Not very aerodnamic, but it is probably quite effective. There are slimline, lightweight type mudguards as used by the Audax (audax.uk.net) and Randonneur people. To reduce spray from the rear wheel, I have seen guards that attach to the seatpost with a simple clamp fixing. It is probably worth a trip to a bike shop to check out the options. There is stuff online that might give you a good idea, for example www.settlecycles.co.uk. Look under mudguards in the "components" section of their product list.

Personally, I dislike putting "stuff" on my bike (stupid vanity really), so I live with the muck, but am able to change & clean up after arriving at work.

Cheers,

Ed