i dont use paper towels. i use a cotton cloth to wipe off the goggles. it works for me, paper towels just arent that great.
an all purpose lens cleaner would be fine i suppose, but i just bring a little squirt bottle of plain water in my bag with me to the field. id use water if i were you.
the only thing you could do to mask the scratches would be to use stickers or sumthing, but that will only hide them and put them out of mind. if they were to get any bigger you wouldnt know. if i were you id replace the lense now before i used it again, just in case. a small scratch on the lens can get bigger and bigger. and then it can crack, and finally break when you get gogged.
i replace my lens fairly often. every time you get gogged you should check more lens to see if theres any cracks or if its loose. and every 5-6 gogs you should change the lens. if im not gettin gogged, i change it every 2-3 weeks.
these prices are for vforce lens from xpaintball.com:
vforce armor lens: $18.77 color: clear
vforce morph/shield lens $26.77 colors:clear, amber, and smoke
mirror vforce morph/shield lens $34.77 colors: blue, gold, and silver
and heres the link to em.
http://xpaintball.com/vforcelenses.html 