Re-numbering rolling stock w/o painting?

I’m a ‘newbie’, so HELLO, and ‘be kind’!!!

I recently recieved, as a gift, a set of Rivarossi passenger cars (PRR); that’s the good news…
The BAD news is; I already had a few of these same cars, altho the I.H.C.-version. They have the same road numbers, from set-to-set.
[:(]
I seem to remember in the last year MR had an article on which solvents to use on which brand rolling stock to remove names & numbers w/o destroying the car-body/paint, but I can’t find the issue in question.
I have no means of stripping & re-painting the cars; if I can safely remove even ONE digit, I can replace THAT digit, to have multiple R.P.O.s, diners, etc., w/ different numbers.
My only other option (gulp!) is to use a fresh #11 blade, and ‘scratch’ away parts of the numbers (I.e.; turn an ‘8’ into a ‘9’; a ‘9’ into a ‘3’, etc. {gulp, gulp!!!})
[:0]
Any help is GREATLY APPRECIATED!!!
[;)]

Some decals can be removed using an eraser. Get an erasing shield like what’s used in drafting and give it a try.

I’ve had success by using a q-tip dipped in an abrasive cleanser.

I’ve seen a rather neat product here in the UK that an enterprising US manufacturer should maybe consider importing - or negociating with the existing manufacturer to make US-outline versions. The product is a set of waterslide decal patches in the same colour as the coach sides - you simply apply the decal over the existing number, then apply the new number on top.