If I rem. correctly about 7 or so years ago I saw an article in Model airplan news about how to make a test stand muffler/catch can out of a paint can, some cat littler and tubing??

Does anyone have any info on how to do this?
or what to use or some diagrams?
Will it affect the engines running any?

I have some old engines I want to fire up and see how they are doing, but the new neighborhood I'm in, if I were to do this in my garage..... Well they wouldn't "appreciate" it
Thanks!