.. Mess & litter-bugs
If your cat is persistently expelling waste material somewhere other than the litter tray, first ensure that you have taken notice of the pages on Litter, positioning & the differing types your cat may prefer. If the behaviour is a sudden change a veterinary check is advised, your cat may be trying to tell you that there is a problem (especially if the waste material isn't regular).
Cats often soil in areas of the household strong with a dominant group scent, on beds & other core areas when they feel insecure. Often what they are trying to do is reassure themselves that they belong & announce that they are present & are an important part of the social group. This activity is a bit like leaving a calling card, signature or "tagging" - as seen in urban graffiti.
New scents brought in on footwear or cycle tires, or scents drifting in from beneath doorways from other cats etc. can also be triggers for this behaviour. Draft excluders &/or replacement doormatts can help.
The most effective way to solve the problem is by working out what it is that is making your cat feel insecure, & tackling the root cause.
Scolding or punishing a cat will only reinforce their insecurity & is most likely to worsen the problem.
Providing a cat/s with a familiar core area, perhaps a room with a catflap in the internal door, where they can feel completely secure is one possible solution. In extreme circumstance the cat may have to be confined to one room & re-trained to use a litter tray. Soft maleable (digable) material such as laundry baskets, rugs etc should ideally be kept off of the floor, while litter trays should always remain on ground level & be kept clean. A solid floor is also ideal for this type of re-training.
If cats spray urine, it should be treated in the same way, the idea is to help the cat to feel more secure & then the problem should lessen & ideally stop.
Some animals spray or defecate for the attention they receive (good or bad, it is often the interaction they seek) or in protest. If this is identified as the reason, when the problem occurs it should be ignored - attention should only be given for positive behaviour. (positive reinforcement)Any mess needs to be cleaned thoroughly to dissipate any scent. This includes the scent of the cleaning process itself as a strong smell of cleaning product (particularly anything containing ammonia!) can also trigger the behaviour. Cats do not like to mess near to where they eat, so once cleaned, dry food can be placed in that area to put them off the idea. A scratch post or matt could also be placed near that spot. This may provide an alternative notice board for them to leave their scent, with the glands in their paws which are activated by scratching. Problem still not solved?
Cats can be rather quirky sometimes & more creative solutions may be required, they may not have learnt the appropriate lessons in kittenhood.
If your cat readilly enters the litter tray but expels beyond its perimiter & none of the litter positioning etc. advice has so far worked, try aquiring a high sided plastic packing crate keeping the lid off. (Enclosed litter trays are not always the answer, many cats will not use them, they may be too confining, claustrphobic, airless & too odoursome. A hole can be cut from the side to create a door, or a catflap could even be fitted.
With a prefered litter then scattered amply inside, your cat should enter, use & leave behind a contained mess - having been unable to project anything over low tray walls.
This could also help with over enthusiastic diggers, who throw litter all over the room.
A litter tray could be placed within a much larger tray or container, that will act to catch any overflows.
If your problem is not addressed here or for more serious or problematic soiling issues, please contact a pet behaviourist such as Vicky Halls
A litterbug may need a little help in cleaning their act up
Simple packing boxes (lids off) with high sides & a doorway cut out, could act as effective litter trays
A fine toothed saw such as a junior hacksaw is best for cutting through potentially brittle plastic that may splinter
Take care to avoid leaving any sharp edges or cracks which could snag fur (it is a good idea to have some duct tape to hand to patch up any little cracks)