A couple of advantages of bright coins is that they catch the light better than tarnished ones so add some flair and are easier for the audience to see. A second advantage is that, unless closely examined for wear, they all appear pretty much the same, especially if they are the same date, so it is less likely that someone will notice that the coin you are showing is not the same coin you showed a second ago.

I like bright coins for effects like Three Fly and Coins Across for others I will use darker coins.

If you want to brighten SILVER COINS here is an easy and cheap way of doing it without scratching the faces or using harsh chemicals.

Do this in a ventilated area because the reaction will give off a bit of a sulphurous smell, it is not dangerous but might smell up your kitchen so a garage or outdoors is better.

1. Line the inside of a small oven safe GLASS (not metal) bowl with aluminum foil, shiny side up. Try to make sure there is
no glass showing through.

2. Put two large tablespoons of baking soda on the bottom.

3. Place the coin to be treated on top of the baking soda.

4. Slowly add BOILING water to fully cover the coin and a little extra.

5. The solution should start to fizz.

When the effervescence starts to slow down give the bowl some agitation to get it going again.

Keep going like that for 3 - 5 minutes or so when the baking soda has pretty much all disappeared.

6. Use rubber gloves to remove the coin (be careful it may still be hot).

Using the rubber gloved hand ONLY gently rub the front and back surfaces of the coin. This minimizes wear to coin.

7. Use a little liquid dish soap and warm water to remove any residue, then rinse with just warm water.

Gently dry with a soft cloth like an old t-shirt. Don't rub hard and don't use anything abrasive.

When softly drying the coin do just enough to dry it off.

8. Heavily darkened coins may need more than one treatment to get them to the luster you want.

DO NOT USE ANYTING ABRASIVE because it will scratch your coins.

Note again this is for SILVER COINS a different solution is used for Copper.

I'd soak it in white vinegar. No heating is required. It may not work on every surface, but I've even removed hard water deposits from plastic with this method. The last time I tried, it worked on an old penny. I'd use Renaissance Wax to keep the patina from forming again.

Use a very soft toothpaste brush and white toothpaste to gently clean, then rinse.

White vinegar is fine for copper coins but not recommended for silver.

Toothpaste is too abrasive.
If you're going to go with a "paste", Wright's Silver Cream is gentler and works great.

Depends on the toothpaste. Some pros do it. Agree that Wright's is good also.

The baking soda rout is a little cheaper, Wright's Cream is about $5-6 a jar, a box of baking soda is about $1.60 and it is likely you already have some in the cupboard.

$5-$6 a jar! The horror!

Posting the days seems to be an existential battle to be right.

Nice reminder of the baking soda + aluminum foil technique. It's been around forever as a method to clean silverware. An advantage of this method is it removes oxidation from recesses and crevices that creams and polishes leave behind, which is why folks suggest using a toothbrush. In fact, in my opinion, this is a primary advantage of baking soda + aluminum foil. Good to know you're happy.

Well I admit to being a bit of a spendthrift. If it saves me a couple of bucks then I can spend it on something else. lol

My uncle called it penurious. Love that word.