Most smoked meats expel fat, which is a quick way to dirty a smoker. Since keeping a smoker clean is easier than cleaning it up, you can avoid the hassle with steam or sheet pans to contain any mess.
Full-size and half-size steam pans
Double smoked ham in a steam pan
How to smoke sausages on an offset pit
How to find hot and cold spots in your smoker
How to use an injection for flavour