Always filter your drugs before injecting - it's so much better for you than not filtering - it's much cleaner for your system.

Filter your shot in the bag. Using a filter will also help prevent puncturing and rupturing the bottom of the deal bag with the pick (sharp end of the fit). The filter covers the fit so that you don't make a hole in the bag and lose the contents.

Also be careful if your drugs are crystalline rock shards, like ice or crystal, as they have very sharp edges - it's best to slowly and gently dissolve the substance in your deal bag. If you add water and mix vigorously there is a good chance a sharp edge will tear the deal bag and you'll feel a wet sensation on your fingers as the drugs leak out.

Mixing up in the deal bag is convenient but you could lose the lot out the bottom of the bag:

• if you use boiling water, or
• the bag is faulty, or
• you accidentally poke a hole in the bag with the fit

Be careful to angle the bag when you put your fit in.

Deal bags aren't perfect either, every now and again you will get a faulty one. If you don't mix up in a hurry you can easily detect this and double up your deal bag to avoid leakage.

Deal bags of powdered speed and base leave residue and it can be very tempting to do a rinse of a few old ones when you run out. You should be aware that there is a risk of bacteria building up over time. If you rinse, keep your own used deal bags in a safe place so they don't get mixed up with other peoples used deal bags.