Aerosols are generally pressurised cans like deodorant, air freshener or bug sprays.
These should be brought to your local civic amenity site and if this is not an option please place them in your general waste bin.
In some parts of the country bring banks accept tins and cans, if this is an option you can place aerosols in these also, please remove any lids.
In Ireland, as per 2nd Schedule category 1 waste of The Waste Management Act, 1996, aerosols fall into the category of hazardous waste and therefore cannot be placed in the household recycle bin. If your contractor uses a facility which incinerates waste then the aerosols can be recovered from the ash and then they will be sent for recycling as the incineration process does not change the properties of the metal.