Run up for plug clearing

The answer to questions such as this can be found in the POH from the
manufacturer who supposedly knows more than the average flight instructor or
public thought about what is right.

For the Cessna Model 152 Section 4 Normal Procedures under "Takeoff" "Power
Check" says
"It is important to check full-throttle engine operation early in the
takeoff run. Any sign of rough engine operation or sluggish engine
acceleration is good cause for discontinuing the takeoff. IF THIS OCCURS,
YOU ARE JUSTIFIED IN MAKING A THOROUGH FULL-THROTTLE STATIC RUNUP BEFORE
ANOTHER TAKEOFF IS ATTEMPTED. The engine should run smoothly and turn
approximately 2280 to 2380 RPM with carburetor heat off and mixture leaned
to maximum RPM."
(Emphasis added.)

You will not harm the engine therefore if you use 2000 RPM and lean to clean
the plugs.

I suggest if you are serious about this you discuss the matter with a
mechanic.