Decals

I have an assortment of passenger cars of various roads and I would like to remove their decals and replace them with road names of my choice.
How can I remove these decals without harming the finish of the car?

 

<font color="336633">What make are the cars? as some can be removed with decal set, some are more difficult</font>

 

There are several Life LIke Budd cars, 2 Spectrum heavy coaches and several sets of what I believe, is Tyco

 

Is decal set some kind of liquid to be applied
to the decal?

 

<font color="336633">Yes it is, best one to use in my opion is the Walthers one, the ones that Microscale make are weaker than a cup of water </font>