Feedback on a problem with water-soluble colored pencils.

A while back I posted a thread about a problem with water-soluble colored pencils...can't find it.  Suggestions were offered, and I've been remiss in not returning to the subject. I don't like using masking fluid.  Usually I leave the white paper for whites.  Often, I need to add white over other colors.  I'd imaged I could do this with colored-pencils, using the white pencil.  Didn't have much joy with that, so I used gouache...that's OK, but I asked if anyone had other suggestions. Robert suggested trying a white Conte pencil.  Alan spoke of a paint he sometimes uses on water-based work. I tried to order them.  I found Alan's paint but they were out of stock temporarily.  I bought a single conte pencil.  (Conte of Paris, pastel 013, white...it's the harder version of their normal white apparently.) I found it much better than the water-soluble white I've been using.  I've not used conte before, when I press hard to get a strong white I get some 'dust' forming.  It's easily brushed away.  (New to me, no doubt commonplace to you conte and pastel users).  I found I could easily soften/blend the white by rubbing it with my finger.  So, this conte pencil will replace the colored-pencil white. Here's a pic I made, where I used the conte-pencil...it's mixed media but mostly colored-pencil.  It's on the gallery, but I've put it here to make life easier. The face was greener, I hadn't left enough white.  The conte pencil, rubbed to blend at the edges, gave me what I wanted.  The wings of the character in the background were simply drawn with the conte pencil.  So thanks Robert and Alan for your advice. By the by, I have to confess this isn't a great reproduction.  There are no yellow patches on my picture, I did use a thin yellow glaze to adjust the green on the girl's face.  On my actual picture it's the green I wanted, and has no yellow patches.  I tried to adjust it in photoshop to make it look like my picture - usually an easy task - but in this case it made things worse.   Odd...but it may simply be that my scanner is on it's last legs.  I've had it for 10 years at least.

Thanks Alan.  Glad you named it again, I couldn't remember and was going to ask.  I'll get some if I can, all the suppliers I tried had it on their stock lists but the white wasn't available.