Surgical tape residue...
Hey there!
The easiest way is to use alcohol wipes -- they break down that residue. I found that out after scrubbing my one arm like crazy. When I went in for blood work, the lab person looked at my arm and asked why it was red. After I told her I had been scrubbing, she told me the secret.
Of course, there are some people who kind of like the gummy residue look!
Take care.