Scriber

I was given a dental pick by an experienced modeller. Don't know if the retail scribers are good or not, but the pick works well.

QT

Check out Squadron.com-I got mine there (cheap). Also, use a guide to keep your scriber on track. Remember-sharp surgical steel on stryene-be careful.

its not hard as a test in extreme patience. a sewing needle worked good; if you hate your fingers. but its super cheap.

however I broke mine after about 3 hours of pushing it.

now I have an actual scriber; fingers are happy and it doesnt break. but if you happen to have a sew-er in the house, it could tide you over.