The formula of offering.

Every spirit should be rewarded some form of offering for the services rendered unto the magician/sorcerer.  But offerings should differ accordingly, as each spirit has a class each offering needs to be particular to the spirit's nature and be presented in an intelligent and formal fashion.

So here is my personal formula:

Super-celestial and Celestial Spirits:
+Angels receive a set period(days, weeks, months) of prayerful praise at one's oratory altar. The words themselves are the offerings, but candles and religious/biblical incense which has been consecrated according to the arts of Solomon or the Church may also be used in conjunction to the prayers.

+Planetary Spirits may receive a set time of praise like above except any incense and candles must be appropriate to the nature of said planetary spirit. Thus a Solar spirit should receive incense that is corresponding to a solar nature and candles which are golden in color. One may also keep the seal of the planetary spirit upon the oratory altar for a given time as an offering.

Sub-celestial, Aerial, Terrestrial, and Infernal Spirits:
 +Aerial Spirits are of mixed natures and thus the way one places offerings unto these spirits differ for the individual spirit that was used. The more gracious of the aerial spirits may have their seal placed near the oratory altar in which the spirit receives praise and thanks for a period of time. If the aerial is more of the unruly kind, it is better for the magician/sorcerer to draw their seal at a crossroads and offer praise and thanks there..

+Geni Locii/Nature Spirits are often location specific and so their offerings should be placed where ever they exist. Good offerings for these guys would be left overs from harvests/gardening, food, grain and beer.

+Infernal Spirits should have their seals drawn at a crossroads with consecrated chalk onto which one may place libations of alcohol, beer, meats, fruit, incense, and etc.