My crown fell off my front tooth and the dentist I went to see wants to charge $850 to upgrade it. In the meantime I am trying to figure out a way to temporarily reattach it. Any ideas of how to a) clean it out and b) reattach

I am confused as to why the dentist didn't just bond it until you can afford the upgrade. Did the cap fall apart? Flossie may have better advice to give but until she shows up... if the cap is in one piece and can be reattached, you can attempt to try as a temporary solution Dentemp OS. It is a "cement" like product that might keep the tooth in place for a short period. You can find it at any drug store or a supercenter such as Walmart's, in the aisle where they sell all the dental products. I have used it as a temporary fill for lost filings, cracked molars, & a loose crown until I could get into the dentist's office and it worked quite well. My crown was over a molar not a front tooth so I can't vouch for how well or how long it will hold. Regarding cleaning it, you might want to try a tiny brush pick with a little hydrogen peroxide and/or baking soda. You should be able to find the brush pick in the same area as the temp filling & floss.

Regarding the price the dentist is charging, it isn't out of line for a new cap. But, can't the old cap be saved? If you aren't sure and are having money issues, try getting a second opinion from another dentist and see if he can at least rebond it for you until you can afford to buy a new one.

If the crown fell off due to decay under it you really need to have a new one made. You certainly don't want to recement the crown over the decay or you could end up with an abscess and need a root canal as well.

A second opinion is always a good idea!