I would not use any solvents, they would only create a residue that may react wrongly with the thinset.
Just use a razor blade scraper and get all possible loose material off, then using a high quality multi-purpose thinset, skimcoat the entire slab with a flat trowel...a very thin coat that you press into the floor as you trowel it on. Let that thin coat dry 24 hours and you'll have a great floor to bond to with the same high quality thinset.
You can identify quality thinset not only by the higher price (usually $15 and up a bag), but the small print on the back of the bag will say that it will adhere to vinyl, existing ceramic tile, exterior grade plywood etc. etc.
When I skimcoat questionable surfaces I use a liquid additive made by Laticrete called "333". Mixed with regular (NOT multi-purpose) thinset, it makes a super strong coating, and an excellent thinset.
Have fun. How were you planning on making the transition from slab to wood flooring area? Those two surfaces will surely settle and move separately. Many grout manufacturers make a sanded caulking that matches their grout colors. I would caulk the joint at this transition with sanded caulking. It shrinks alot when filling a large gap (1/4" typical joint), so you may need to apply it again after the first application shrinks.
thetiler