More often than not, you are fly fishing and suffer a tangle of your rigging. The tangle has to be re-rigged and the problem is at the tip of the rod or leader. The angler sets the rod down reel first and often onto a hard surface (rocks). Aside from the cosmetic damage of abrasion to the reel, there is a bigger problem that can cause serious damage to your reel: the reel hits the surface with enough force (it does not take much force) to bend the outer rim of the reel’s spool and crimp that inner slot that fits against an inserted flange that helps stabilize the spool to the reel housing. What results is either a reel that will not turn or turns with an intermittent grinding.
This is a very hard ding to fix and most people don’t have the machinist capabilities to return the reel to normal. Given the price of reels and spare spools, you might want to pause and look where you are about to set that reel down. You will hopefully avoid the grit, abrasion and dings that cause serious damage to your reel.
SwittersB & Exploring 
the groove on the spool can be reshaped using ball embossing tools. soak a scrap of leather in silicone lube, take a tool smaller than the groove and work the groove open. make sure you lay the spool on a glob of putty or play-doh so that you don’t scratch things up any worse than they are. it will take awhile and it may take a progression of sizes, but it works. when i was new to bifocals i went ass over teacup into a colorado stream and a brand new lamson was dinged. an jeweler showed me how to work the spool back into shape.
if the face of the spool is depressed, try clamping the spool (frame side) to something rigid. then use a spreader clamp to push the ding up. finesse not brute force is the order of the day.
i saved a scientific angler (hardy) system7 that way.
the same day i had picked up a hardy lightweight with a broken frame. i straightened the rim (using the same clamp method) but still had the fracture to contend with. after much agonizing it struck me that radiator shops did thin-wall aluminum welding. a neighborhood shop did the work at a very reasonable cost and i now have a great little reel.
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Thank you Craig. I have my original Marryat in a drawer, from a crash on the Crooked River, years ago. Maybe there is hope.
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Yes, I have seen these neoprene like covers (by Simms) that one puts on when hiking in or wading. Not a bad idea. When working on the rod shore side I am not sure I would use one, but given the price of some reels and spools I might under the right circumstances.
SB
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