Bulk changes to capitalize tags

You cannot make such bulk changes, and even if you could, we don't usually want you to. There are a number of reasons against bulk changes (changes that happen without the person making the change actually seeing the object they are changing).

First of all, you might not be as correct as you think you are; other people in the same region might not agree with you. Therefore you have to seek agreement before making bulk changes.

Second, especially if you are new to OSM, you can easily make mistakes when bulk editing, for example, there could be a night club called "CL45A" and because you haven't thought about your process enough (and not discussed it with others), you might erroneously change that to "Calle 45A" too.

Third, bad naming and capitalisation errors can also be a good signal that more work is required in an area; someone who didn't manage to get the street names right might also have introduced a lot of other mistakes. By mass-fixing the street names you would make things look better on the surface without investing the time that the area in question might really need - better to leave things as they are until someone comes along who actually knows the area and can give it a make-over in a proper editor.

Please re-think your desire for a quick mass fix; it doesn't actually improve OSM as much as you might think. Instead, pick a small area you are familiar with, and give that area some love, with a standard editor like everyone else does. That will be much more valuable to OSM than a quick search-and-replace of street names.

A bulk edit can work well if done right so don't rule it out completely, but do take heed of Fred's advice as there have been too many bad bulk edits done in the past.

Talk with the local community and come up with a plan. It may well turn out that there are too many potential pitfalls to doing it on an automated basis. If so, you still have options, where you can do it in a semi automated way by using something like MapRoulette.

http://maproulette.org/

Seems like the best way now is to use Level0 - in Overpass Turbo, use export - level0, get the data into the edit window, copy/paste it into your text editor, make changes, paste it back to level0, validate, and either export to JOSM (download .osm file), or upload directly if you are logged in.

The quickest way to manually go through large numbers of objects in a town sized area, checking and fixing each one as needed, is by using JOSM with the ToDo plugin.