Applying apple cider vinegar for backne?

ive been useing AVC (apple cider vinegar) for my backne just started and i was wondering if im applying it right i use a spongy like thing u kno those things that come with body wash (which i dont use) ive been putting it on that and applying to my back then rinseing out the ...spongy thing lol i cant use tissues or cotton cuz it uses too much and it'd be expenseve after a while. can i just apply it with my fingers? also i use just AVC i dont add water and i dry myself befor i put the AVC on then i put my clothes on after i apply it is this right?