scratch at

scratch at something

to scratch something. You shouldn't scratch at a chigger bite because it might get infected. Don't scratch at it!
See also: scratch
References in periodicals archive ?
With Sexy Scratch Off, users can choose any one from a list of adult stars and then use the touch screen to remove the model's clothing one scratch at a time.
Using the newly constructed light scattering instrument at NIST, optical scattering measurements on a single scratch at various scattering geometries collecting both the specular and nonspecular intensities were conducted.
Fine cracks extend from both sides of the scratch at an angle of about 30[degrees] to the scratch in specimen T3 (Fig.
The plastically deformed matrix also contains parabolic marks with fine cracks extending from both sides of the scratch at an angle of about 30[degrees] to the scratch (Fig.