I very much doubt if a coin would degrade to VF through being stored in a folder. If handled significantly, then it could go down to EF+ but pictures would help us.
VF is a comparatively misunderstood grade that has actually changed over the years. Back in the 60s it was defined (I paraphrase) as "visible wear only to the highest points of the design", and it was strictly interpreted by the top dealers. However, there has to be a clear divide between EF and VF to account for difference in values. I would say that VF shows the complete design but can appear a bit 'blurry' due to the wear to - e.g. lions' faces, garter motto, monarch's hair, etc. If you want pictorial guidance, then invest in Derek's book on grading British coins as shown in the banner ad, top.