If your paint/clear coat needs a minor bit of work, a very good pre-wax cleaner is Gel-gloss. This is a very gentle product though not specifically for cars and sold at Home Depot and other hardware stores. It works very well for gently rubbing out your ride to bring back that lost luster. Use a clean soft cloth to apply to small area and another clean soft cloth to buff. Do not apply to warm or hot metal.
If that doesn't work, try No 7 White Polishing Compound" (not the heavy duty). This is a little more abrasive than the Gel-gloss but won't harm a clear coat if you don't grind it in.
I use both of these products successfully on a regular basis, either by hand or with a buffer. They will not harm a clear coat if applied properly. If you use a buffer, practice on another car first.
For the interior I use "folex" carpet and fabric cleaner. you can find it at Home Depot. a gallon costs about $16. it works on your clothers as well.
For really stubborn bugs, road tar and other sticky stuff you might try "goo-gone" or "goof-off", both from Home Depot or your local hardward store. This is in liquid form and petrochemical so don't spill it on anything. This is not a polishing product so apply it with a **cue tip to cover only the affected area** and rub gently for awhile. This is a last resort cleaning method. Wipe off any residue as soon as possible.
You'll need to wax after each of these products is applied.
If you have any black rubber/hard rubber trim try Black Again to bring back the deep black color.
The above is based on my experience so, as always, when you try a new product test it in an inconspicuous spot first to determine if it works for you in your situation.
So Goof-off is bad. I see. HOw about Goo Gone? I got a bottle at home, but I have never tried it on my car. I have some small bit of stubborn tar at the front spoiler of my car. I have been rubbing but nothing works. Should I try a clay bar first? :thud