If what is remaining from the removal of scuff sheets/tape is sticky, then a quick wipe with a cloth soaked in white spirit followed by scraping it with a credit card should get rid of it. If there isn't very much of it or the leftover is quite dry, almost chalky/flaky like really really old fibreglass tape then a sanding should remove it easily, but it can clog the sandpaper costing £'s in the long run.
A power sander will save you a lot of elbow grease! If you are going to hand sand be prepared to put in some long hours, i reccomened buying a sanding block too. The grades I have are:
80 - not always used, mainly there for really stubborn adhesive or sticker shadow.
120 - the grade I usually start with. Cleans up most bats nicely, coarse enough to work out seam marks and small cracks but gives a decent enough finish to move into a higher grade without much worry.
180 - see above, I sometimes start here if the bat is in very good nick.
220 - this grade is more about polishing than sanding really, this is where you start to see the bat come back to life.
240 - progressing on with the smoothing/polishing effect by now.
320/400/I've even got some 600 and 800 somewhere! - finish off the polishing effect, you will barely remove anything with these grades, but will generate a lovely finish.
Don't skip a grade of sandapaper. I don't mean you have to use the exact number I have, but don't go straight from 80 to 360 etc, this will ruin the finish!
After that I remove all the dust etc (usually by wiping on my clothing or with a microfibre cloth) and then apply some Lord Sheraton Wood Balsalm, salix bat wax is an alternative, but I find the wood Balsalm easier to use as it has a much softer consistency, my salix bat wax is very hard, like candle wax! Lord Sheraton is like butter that has been out the fridge for a day.
After applying the Balsalm or wax, leave to settle for a while and then buff to a lovely finish.