If you simply have no swimming beaches in your area (either lakes, or ocean), a possible alternative to turf, is sandboxes, or sand-volley-ball courts. Sand is much easier digging.
But if you simply must do turf, bear in mind that some forms of turf have higher ratios than others, for junk vs gold items. The utmost worst turf is always going to be picnic areas. Those would be where your picnic benches are, and worse yet; if BBQ pits/stands are there. Because anytime you get people eating and drinking (and worse yet cooking), is an automatic foil and tabs. Thus the type turf that will be more condusive to jewelry ... with less junk, is going to be turf totally dedicated to sports. That can be soccer, football, and base-ball. The more "frolicking" (ie.: movement, tumbling around, wrestling motions, etc... ) the sport, the better. The type parks where people set out picnic blankets to eat on, will naturally have more junk. But when you think of it, no one sets out their picnic blanket on baseball fields, soccer, football, etc.... right? Thus there are different types of turf.
As for the rest of your question, there is no magic formula as to what signals will be gold, verses aluminum (they both share the same conductive ranges). However, there are some people who have, over the years, made "ring enhancement programs", which seeks to study where the majority of gold rings fall on the scale, verses the most commonly recurring junk items. So for example, someone takes 1000 random gold rings (like if they had a friend who owns a jewelry store), and plots their TIDs on a computer spread sheet. Then he takes 1000 randomly occuring junk items (taken from a stroll in a junky park with his disc. set to wide open). He plots all them on on the same spreadsheet. Then he comes up with which #'s are the most likely.
Of course those "ring enhancement programs" sort of go out the window, if you're in a park where lawn-mowers have reduced cans to can slaw, or where prolific amounts of larger wads of foil exist. But assuming you're in a park where the tabs are pretty much all uniform (and not cut up), then you can start to play the odds, and pass the most commonly recurring junk items. Be assured though, you will miss some gold doing this, but ....... oh well. But combined with choosing the right turf to begin with, it might cut down on your time spent digging.
good luck & HH Tank
