For most banks, cashing in your penny jar is something they do only reluctantly. You have to manually sort the coins into single denominations. You must manually bag them into precise quantities. Even though they have the high-tech, industry-precision, scales to do it automatically.

There are some machines in supermarkets which will process your pennies automatically... for a 10% fee. This, to me, is as bad as cash machines which charge you �2 for access to your own money. So I always sort and bag my own penny jar.

This Instructable details some ideas, tricks, and tips, on how to this quickly, efficiently, and accurately. For example, I recently sorted 3650 coins into money bags totaling �242, in an hour and a half... without miscounting a single penny!

Step 1: Prepare Your Area

This is fairly simple, but has some common-sense rules:

Find a flat surface - this ensures each pile is equal in height, making it easy to spot missed coins. Carpets are generally not good for this. Kitchen lino is good, and large enough.
Tip the coins from the jar/bag/whisky bottle onto the surface, and make it fairly flat - this ensures maximum visibility.
Put on a good LP. Don't use an MP3 player! An LP forces you to get up, and change posture, every 20 minutes giving you body and mind a quick break.
Plan additional areas for:

shiny new coins you want to keep/display
foreign coins (there will always be some)
stacks of sorted coins
empty bags (usually behind you)
full bags (these don't need to be close, as they can be thrown)
large denomination coins. There's not usually enough in a penny jar to make up a full bag, so don't waste time sorting these out until the end.
one empty bag, with the coin legend visible. i.e.. �1 of 1p or 2p
Sit in the middle of these areas, with each section in easy reach.

Step 2: Sorting the Coins

This is actually more fun than it sounds. It's game, remember. How quickly can you sort then? How many coins have you coin? Can you guestimate the total value?

Some tips for the process itself:

Take single coins, one in each hand.
Look for the next pair of same denomination coins as you pick up each pair.
Take 10 coins in each hand, but count the coins individually. i.e. up to 20. You can then either stack them in piles of 10 (as 10x10p = �) or 20 (as 20x5p = �) without changing your workflow for each denomination.
If you can't immediately seen more coins, look elsewhere in the pile. Don't waste time tying to uncover coins in any specific area.
Switch denominations periodically, whenever you notice a large number of a particular coin. This will happen automatically over time as all the copper disappears, and you're left with lots of silver.
Place the coins in stacks, and let the stacks run over your fingers. This helps you feel for coins that are slightly larger, or smaller, than they should be. Tip your hand slightly as you place the stacks down to make this easier.
Do everything in pairs. i.e. Place stacks together, so you can compare the heights against each other to make sure you're accurate.
Keep the stacks into groups of 5 or 10. When you notice your unsorted coins are dwindling, this'll give you a clue as to whether it's worth looking for more, or if there aren't enough coins left to make up a full bag.
Don't try and create running totals, it'll just divert you.
Do switch position: kneel, cross legged, etc periodically.

Step 3: Bagging the Coins

Do it whenever you're running low on stacking space, or need a break.

This is an easy and obvious thing - just take care to not spill coins. You can use kitchen scales to get an approximate weight test, which is good if you can't remember if you added 9 or 10 piles of coins to a bag.

With practice you can gather two side-by-side piles of coins at once by pushing them together into a v-shape.

Step 4: Now Wash Your Hands!

Then lug the whole lot down to the bank before they shut. Take a route that avoids beggars. Not that they're likely to be able to run with the weight of all these coins - but when carrying your penny jar to the bank, it's impossible to hide a smirk when you hear the phrase "got any spare change" ;)

Make your own notes of how many coins, of each denomination, you have as the bank teller is likely to make a mistake or two.

Take a separate bag of pennies, just in case you miss a coin here or there. You don't want to lug this sort of weight any distance.

FWIW, my penny jar also had: