This is indended to replace potentially convoluted code involving lots of loops and calls to setchar().
What this command does is it looks at the line specified (from 1 to 25), and blanks out everything that is marked as 'graphics', no matter where in the line. This, effectively, allows you to strip out graphical logos and 'clean' the page.
Example
Here is a frame before smart clearing:
And here it is after smart clearing:
Specifics
Windows: You can specify line 0 to clean the entire frame in one go.
