Home file aharpening follow-up

[porthos]

i posted a thread last week or earlier about sharpening files. got a lot of good responses using different acids. however, i thought that i would try strong vinegar ; a 30% solution. soaked about a dozen files for 2 days. removed from solution water washed and put outside in the sun. they dried quickly and turned rusty. i then soaked them in kerosene. after wiping them dry; they were noticeable sharper. after that i threw the rest of my files in the vinegar about 25-30 or so. mostly 8-10 inch and some 14 inch. i got the vinegar on amazon prime (free shipping) $23.00 shipped. if i do this again after i run out of 30%; i might get 45%