A dull razor can be usefull.

I picked up a vintage razor http://straightrazorpalace.com/begin...012-honed.html that I will send off in the future to get honed. In the meantime I periodically stand in front of a mirror and practice technique with it using no soap, cream, etc. I've found areas of my face to be cautious at where the blade will dig in with specific angles or directions. When this happens I think to myself "damn, I'm glad this thing isn't sharp". It also serves to exfoliate as the blade ends up with flakes of dry skin. :D

I actually still do that now...before I knew any better...(not that I know a lot now..) I bought a Kreiger blade at a festival thinking it was a good deal..
Anyway. I used that to practice my routes along the face and chin as well. Since that is the only thing the blade is good for...does not even go through warm butter /me giggles.

Just make sure the razor is truly dull when you try this practice routine. Most razors folks consider to be dull may not shave but are still in general terms sharp and can do some real damage. Usually we recommend actually grinding off the edge so the razor won't do damage of any kind.

I think they can be useful for a lot of things... Before I stropped with anything decent I grabbed a clunker and practiced with that and the same with learning honing strokes. It's kinda nice to have a beater around that you can, potentially, make mistakes on yet not lose much. I plan on doing the same thing as I start to learn to restore razors... I'll take a clunker apart, clip the pins then practice rolling the ends over with a ball peen hammer on the old ones before I try to use new stock.

I like the dull, rusty, clunky, junky stuff... On top of telling a cool story, they can really come in handy.

I've used a butter knife to practice :)

A dull razor is also good to practice your stropping.

Practicing on a new strop with a sharp blade can often lead to nicks and cuts for an inexperienced stropper. They say to practice with something like a pencil, etc, but I think a dull blade may also work well.

I think it's a great idea to do practice that way. Now that you have done it a couple of times, up your game a bit. Throw on some shaving cream and try it.

You might be surprised to see some of the area's that you miss. This is kind of important because it's those area's that you'll inevitably use more pressure to get to or at. If you use a dull blade to practice and focus on not using pressure, when you hit a spot that you didn't get all the cream - try using a different angle rather than pushing down on the blade. It'll pay huge dividends later!!

Good luck!