Strange as it sounds, sometimes people with dementia forget the purpose of a trash can. This can result in three different, vexing behaviors. Here's how to cope.
Trash mistake #1: Rummaging
Your loved one may rummage through the trash routinely, especially if prone to rummaging behavior generally (going through a desk, a drawer, or papers, for example). The reason seems to be that some people simply find it satisfying to dig through things -- it's a tactile, repetitive activity.
Solution: Relocate an open trash bin to behind a cupboard door -- possibly closed with a child safety latch. Secure outdoor trash containers with bungee cords. You might also substitute a "junk drawer" of things like tool parts or sewing notions for safer rummaging.
Trash mistake #2: Storing or hiding
Your loved one may decide the trash is a good place to store (or hide) important things -- the trouble is that nobody else knows, and/or your loved one forgets, and the items are lost forever.
Solution: If your loved one likes to hide or "file" objects like mail, keys, TV remotes, glasses, and so on, develop the habit of making a quick garbage check before you set out trash for pickup.
Trash mistake #3: Wastebasket as urinal
Men with dementia sometimes use the trash container in place of a commode, especially if they have a problem such as urge incontinence that makes them need to urinate quickly. The wastebasket may be what they see first, and therefore use first.
Solution: Store the bathroom wastebasket inside an enclosed cupboard. If you don't have such a storage spot, try keeping it behind a shower curtain, so other family members can still use it. (Keep cleansing wipes or spray cleaner in easy reach to give the tub a quick clean before using, though fortunately most bathroom wastebaskets aren't too messy.) If your loved one is urinating in other containers around the house, be sure to schedule a medical checkup so that urge incontinence can be treated.