Re: TA cranks.
A chain is as strong as its weakest link and a crank is as strong as its weakest point.
A deep gouge could promote a failure. Better to file / sand them out completely and polish. The gouge may be outside a high stress area anyway. The truth is many of us (40 / 50 year olds?) would be well within the safety limits of hardware, particularly with a classic bike.
If the cranks are anodised, you'd lose the finish and oxidation would occur at a faster rate.
David Fryer, sunny Queensland