I assure you that none of the many Chinese visas I have in my current and previous passports will budge. Nor any of those from other countries. Removing visas is never a good idea and could come back to cause you problems later. Again, best strategy is to keep track of your remaining free pages and upcoming travel, and plot out when to get more pages added.

At least US citizens have the option of getting pages added (and for free)--many other countries won't do add-ons and require you to get a completely new passport.