To elaborate, the difficulty is that most open source Common Lisp implementations do not really provide a facility to strip out the compiler or disable all the core entry points, which means that while probably
the source itself cannot be retrieved from binary code, any limitation you put in place will be relatively easy to override. Commercial ones do, of course, because they are commercial.
If you do not expect any of your customers to be at all familiar with Common Lisp though, you could probably use the same techniques you would use in any other language. I do not know what they are, but you should probably look somewhere not-lisp specific, as this particular distribution mode is not that common in lisp world, I believe.
Also, probably for distributing small programs, of free implementations, ECL
is best, since it does compile through C and can leverage most of the C runtime, which can be expected to be on any target machine, with only a small [1.5 MB] Lisp library, as compared to SBCL 40MB cores, or even CLISP 5.5MB images.